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23/06/2014, 09:00
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Dr Martha Constantinou (University of Cyprus)23/06/2014, 09:15Talk
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Chris Bouchard (The Ohio State University)23/06/2014, 10:00Talk
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Prof. Michael Mueller-Preussker (Humboldt-Universitaet zu Berlin)23/06/2014, 11:15Talk
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Alexei Bazavov (University of California/University of Iowa)23/06/2014, 11:45Talk
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Kim Maltman (York University, Toronto)23/06/2014, 14:15TalkWe propose a hybrid strategy for the lattice evaluation of the leading order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon. The strategy combines direct numerical integration of lattice data for Q^2 greater than Q^2_min with the use of fit forms to handle the lattice data in the low-Q^2 region Q^2 less than Q^2_min. Using a physical model for the I=1...Go to contribution page
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Mr David Scheffler (TU Darmstadt)23/06/2014, 14:15We study chiral restoration and deconfinement in two-color QCD with two flavors of staggered quarks using a RHMC algorithm on GPUs. We measure the chiral condensate and the corresponding chiral susceptibility over the lattice coupling across the finite temperature transition. Using Ferrenberg-Swendsen reweighting we extract the maxima of the chiral susceptibility in order to determine...Go to contribution page
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Dr Leonardo Cosmai (INFN)23/06/2014, 14:15We present results on the curvature of the critical line of QCD with 2+1 HISQ fermions at nonzero temperature and quark density obtained by analytic continuation from imaginary chemical potentials. Monte Carlo simulations are performed by means of the MILC code suitably modified to include a nonzero imaginary baryon chemical potential. We set the chemical potential at the same value for the...Go to contribution page
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Dr Ran Zhou (Fermilab)23/06/2014, 14:15Electromagnetic effects play an important role in many phenomena such as isospin symmetry breaking in the hadron spectrum, hadronic contributions to g-2, etc. We have generalized the MILC QCD code to include the electromagnetic field. In this work, we focus on simulations including charged sea quarks using the RHMC algorithm. We explain the algorithm, code performance, and results...Go to contribution page
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Dr Donald Sinclair (Argonne National Laboratory)23/06/2014, 14:15We perform lattice simulations gauge theories with fermions in non-fundamental representations of the gauge group, which might be models for Walking Technicolor theories. In particular we update results reported earlier on SU(3) gauge theory with colour-sextet quarks. In addition we will report on results (if any) obtained for SU(2) gauge theory with colour-adjoint fermions.Go to contribution page
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Dr Mario Kieburg (University Bielefeld)23/06/2014, 14:15A finite lattice spacing may have a crucial impact on the phase diagram of QCD. The existence of the Aoki phase for Wilson fermions underlines this point. Sharpe and Wu already showed that this kind of lattice artifacts carry over to finite twisted mass. The next task is the calculation of the phase diagram at finite chemical potential. I will present the phase diagram of Wilson fermions of...Go to contribution page
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Mr Brendan Fahy (Carnegie Mellon University)23/06/2014, 14:15Progress in calculating scattering phase shifts on Nf=2+1 anisotropic clover Wilson lattices is described. The stochastic LapH method facilitates computations in large volumes and for light pion masses. Results for pion masses down to 250 MeV, keeping m_pi L > 4, are presented.Go to contribution page
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Dr Meifeng Lin (Brookhaven National Laboratory)23/06/2014, 14:35Lattice QCD has entered the era of simulations directly at the physical quark masses thanks to the increasing computing power and algorithmic advancement. But the computational cost for such simulations is still extremely high, both for the gauge field generation and the measurements of physical observables. Adaptive multi grid (MG) algorithm has proven to be quite effective in reducing the...Go to contribution page
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Mr Philipp Scior (TU Darmstadt)23/06/2014, 14:35We compare SU(2) Polyakov loop models with different actions with data from full two-color QCD simulations around and above the critical Temperature [1,2]. We then apply the effective theory at finite temperature and density to extract quantities like Polyakov loop correlators, effective Polyakov loop potentials and baryon density. [1] Smith et al. , Phys. Rev. D88 (2013) 054020 [2]...Go to contribution page
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Derek Horkel (University of Washington)23/06/2014, 14:35In this talk, I will summarize recent work with Prof. Stephen Sharpe in mapping out the phase diagram and pion spectrum for chiral perturbation theory with twisted-mass fermions in the presence of non-degeneracy between the up and down quark and discretization errors. I will show how the CP-violating phase of the continuum theory, which occurs for sufficiently large non-degeneracy, is...Go to contribution page
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Ms Cynthia Yu-Han Huang (National Chiao-Tung University, Taiwan)23/06/2014, 14:35We present the phase structure for SU(2) lattice gauge theory with 8 flavours of staggered fermions in the fundamental representation. One bulk phase transition is observed through the measurement of the plaquette, smeared Polyakov loops, as well as the Dirac operator eigenvalue spectrum. To further identify the order of the bulk phase transition pertaining to confinement and deconfinement, we...Go to contribution page
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Dr Bastian Knippschild (HISKP, University Bonn)23/06/2014, 14:35Pi-Pi scattering is investigated for the first time for N_f=2+1+1 dynamical quark flavours using Wilson twisted mass fermions. Lüschers finite size method is used to relate energy shifts in finite volume to scattering quantities like the scattering length in the I=2 channel. The computation is performed at several pion masses and lattice spacings utilysing the stochastic LapH method,...Go to contribution page
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Michele Mesiti (University of Pisa & INFN)23/06/2014, 14:35We present preliminary results regarding the curvature of the critical line of N_f = 2+1 QCD with physical quark masses. We make use of the stout improved staggered fermions formulation, with a tree level improved Symanzik gauge action.Go to contribution page
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Dr Anthony Francis (Helmholtz-Institut Mainz)23/06/2014, 14:35TalkWe extend our analysis of the leading hadronic contribution to the anomalous magnetic moment of the muon using the mixed representation method to approach the physical point. We present results derived from local-conserved two-point lattice vector correlation functions, computed on a subset of light two-flavor ensembles made available to us through the CLS effort with pion masses as low as...Go to contribution page
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Mr Greg McGlynn (Columbia University)23/06/2014, 14:55We determine the scaling behavior of the autocorrelation times of observables constructed from the topological charge density on lattices with periodic and open boundary conditions using a series of high-statistics numerical simulations. The autocorrelation functions of such observables turn out to obey a simple differential equation which allows the motion of topological charge in hybrid...Go to contribution page
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Dr Shinsuke M. Nishigaki (Shimane University)23/06/2014, 14:55We evaluate the individual distributions of four smallest eigenvalues from chiral random matrix ensembles interpolating chGSE and chGUE by the quadrature method applied to the Fredholm Pfaffian of dynamical Bessel kernel containing a crossover parameter. These distributions are then fitted with the staggered Dirac spectra of the quenched SU(2) lattice gauge theory in the presence of...Go to contribution page
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Mr Thibaut METIVET (CEA Saclay)23/06/2014, 14:55for the BMW Collaboration. We use 2HEX smeared gauge configurations generated with the Nf=2+1 clover improved Wilson action to investigate pion-pion scattering in the rho channel. The range of lattice spacings (0.054 fm to 0.12 fm) and space-like extents (32 and 48) allows us to extract the scattering parameters through the volume dependence of the effective mass according to Luscher's...Go to contribution page
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Prof. Chiho Nonaka (Nagoya University)23/06/2014, 14:55We investigate the structure of the phase diagram of QCD at finite isospin chemical potential with Wilson fermions. From the behavior of meson correlators in temporal and spatial directions, Polyakov loop, isospin density and susceptibilities as a function of isospin chemical potential at zero and finite temperature, we extract the QCD phases at finite isospin chemical potential...Go to contribution page
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Dr Hideo Matsufuru (High Energy Accelerator Research Organization (KEK))23/06/2014, 14:55We numerically study the SU(2) gauge theory with many flavors. Dynamical simulation is performed with the standard domain-wall fermions in fundamental representation at numbers of flavors Nf=2,4,6, and 8. Nf dependence of the static potential, meson spectrum, and the eigenvalue spectrum of the Dirac operator is investigated so as to determine the phase structure.Go to contribution page
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Dr Georg Bergner (ITP Goethe University Frankfurt)23/06/2014, 14:55The effective Polyakov loop theory reproduces the main features of the Yang-Mills theory and QCD at finite temperature. A systematic derivation of the effective theory is a combined strong coupling and hopping parameter expansion. It includes a systematic ordering principle of the effective couplings. I will review this approach as well as results and possible applications. Furthermore, I...Go to contribution page
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Ms Vera Guelpers (University of Mainz)23/06/2014, 14:55TalkThe hadronic vacuum polarization can be determined from the vector correlator in a mixed time-momentum representation. We explicitly calculate the disconnected contribution to the vector correlator, both in the $N_f = 2$ theory and with an additional quenched strange quark, using non-perturbatively $O(a)$-improved Wilson fermions. All-to-all propagators are computed using stochastic...Go to contribution page
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Mr Tiago Jose Nunes da Silva (University of Groningen)23/06/2014, 15:15We discuss our results on the thermal phase transition in color $SU(3)$ QCD with a large number $N_f$ of fundamental fermions using lattice gauge theory. We study the dependence of the critical temperature $T_c$ of the transition and of the coupling at $T_c$ on $N_f$. These results are used to investigate precursory effects of conformality associated with the emergence of a non-trivial fixed...Go to contribution page
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Mr Tadeusz Janowski (University of Southampton)23/06/2014, 15:15I will present preliminary results on K-pi scattering lengths obtained by the RBC-UKQCD collaboration. The results are obtained using one of our domain wall fermion ensembles with physical quark masses. I will argue that the large "around-the-world" effects which are present with such light quark masses can be controlled.Go to contribution page
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Prof. Lorenz von Smekal (TU Darmstadt and JLU Giessen)23/06/2014, 15:15In G2-QCD the SU(3) gauge group of QCD is replaced by the exceptional Lie group G2. This replacement leads to a theory that does not have a sign problem and can be simulated at finite baryon density using standard lattice techniques. The price to pay is that it contains bosonic as well as fermionic baryons. The physics of the light bosonic baryons is expected to be analogous to other QCD-like...Go to contribution page
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Mr Mikhail Denissenya (University of Graz)23/06/2014, 15:15We study the iso-scalar and iso-vector mesons under the exclusion of the low-lying Dirac modes from valence quarks with the overlap operator within the two flavour lattice QCD. We study mesonic correlators and extract states at each level of such low-mode truncation. Our observations support a simultaneous restoration of both SU(2)_L \times SU(2)_R and U(1)_A symmetries. We finally observe...Go to contribution page
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Mr Matthias Rottmann (University of Wuppertal)23/06/2014, 15:15The overlap lattice discretization of the Dirac operator preserves the important physical property of chiral symmetry, at the expense of requiring much more effort when solving systems with this operator. We present a preconditioning technique based on another lattice discretization, the Wilson-Dirac operator. Recently, close to normal operators have gained popularity in numerical simulations....Go to contribution page
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Mr Tobias Rindlisbacher (ETH Zurich)23/06/2014, 15:15We study QCD with Wilson fermions in the presence of an isospin chemical potential mu_I. At zero temperature, condensation of iso-positive pions is expected to occur as soon as mu_I reaches half the pion mass. By looking at the isospin density and the mass spectrum of mesons as a function of mu_I, we investigate this pion condensation on the lattice and extend the study to non-zero...Go to contribution page
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Ms Bipasha Chakraborty (SUPA, School of Physics and Astronomy, University of Glasgow)23/06/2014, 15:15TalkWe describe a new technique (presented in arXiv:1403.1778) to determine the contribution to the anomalous magnetic moment (g-2) of the muon coming from the hadronic vacuum polarization using lattice QCD. Our method uses Padé approximants to reconstruct the Adler function from its derivatives at q^2=0. These are obtained simply and accurately from time-moments of the vector current-current...Go to contribution page
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Dr Junichi Noaki (KEK)23/06/2014, 15:35We report the status of 2+1-flavor simulations with the Mobius domain-wall fermions on fine lattices of 1/a = 2.4 and 3.6 GeV. The violation of the Ginsparg-Wilson relation is controlled at the level of 0.5 MeV or better. Analyses of the Wilson flow observables, heavy quark potential and light-hadron correlator are presented.Go to contribution page
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Mr Luchang Jin (Columbia University)23/06/2014, 15:35TalkThe anomalous magnetic moment of muon, g-2, is a very precisely measured quantity. However, the current measurement disgrees with standard model by about 3σ. Hadronic vaccum polarization and hadronic light by light are the two types of processes that contribute most to the theorectial uncertainty. We will discuss the light by light lattice calculation and some strategies of including QED...Go to contribution page
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Dr Bjoern Wellegehausen (JLU Giessen)23/06/2014, 15:35G2-QCD is a QCD-like theory with fermionic baryons and fundamental quarks. Unlike QCD it does not suffer from a fermion sign problem at finite baryon density and therefore allows to investigate effects of fermionic baryons on the G2-QCD phase diagram with standard Monte-Carlo methods. In the talk we present recent results on the phase diagram at zero and non-zero temperature with an...Go to contribution page
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Dr David Wilson (Old Dominion University)23/06/2014, 15:35We have obtained clear signals of resonances in coupled-channel pi K - eta K scattering. Using distillation and a large basis of operators we are able to extract a precise spectrum of energy levels using the variational method. These energies are analysed using inelastic extensions of the Luescher method to obtain scattering amplitudes that clearly describe S, P and D wave resonances,...Go to contribution page
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Prof. Bernd Berg (Florida State University)23/06/2014, 15:35We compare the non-perturbative SU(3) lambada scale of Necco and Sommer with the lambda scale derived by Bazavov et al. from deconfining phase transition data of the Bielefeld group and others. Though the relative discrepancy is never larger than 2%, it matters in some applications. Differences are encountered between results from the set of smaller lattices of Necco and Sommer and ...Go to contribution page
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James Osborn (ANL)23/06/2014, 15:35I will give an introduction to the FUEL project for lattice field theory code. The code being developed (called "qhmc") was initially targeted for gauge field generation for beyond standard model theories, and is now growing into a more general framework suitable for analysis too. The design is based on using the Lua scripting language as a wrapper for existing lattice field theory...Go to contribution page
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Mr Oscar Akerlund (ETH Zurich)23/06/2014, 15:35We study two exactly solvable conformal models, the critical 2d Ising model and the Sommerfield model on the lattice. We find that some conditions on the geometry of the lattice must be fulfilled in order to obtain results free of systematic errors. In the Sommerfield model we also introduce a mass deformation and measure the mass anomalous dimension, $\gamma_m$. We find that the...Go to contribution page
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Dr Naruhito Ishizuka (University of Tsukuba)23/06/2014, 16:30We presnet our results of the $K\to\pi\pi$ decay amplitudes for both the $\Delta I=1/2$ and $3/2$ channels. Calculations are carried out with $N_f=2+1$ gauge configurations previously generated by the PACS-CS Collaboration with the Iwasaki gauge action and nonperturbatively $O(a)$-improved Wilson fermion at $a=0.091\,{\rm fm}$ and $m_\pi=280\,{\rm MeV}$ on a $32^3\times 64$ ($La=2.9...Go to contribution page
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Prof. Ting-Wai Chiu (National Taiwan University)23/06/2014, 16:30We study the charm physics in two-flavors lattice QCD with optimal domain-wall fermion. The gauge ensembles are generated on the $24^3 \times 48 $ lattice with the extent in the fifth dimension $ N_s = 16 $, and the plaquette gauge action at $ \beta = 6.10 $, for three sea-quark masses corresponding to the pion masses in the range 265-465 MeV. We determine the lattice spacing by the Wilson...Go to contribution page
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Dr Piotr Korcyl (DESY Zeuthen)23/06/2014, 16:30We report on the status of large volume simulations with 2+1 dynamical quarks which are being performed by the CLS collaboration. The algorithmic details include: open boundary conditions, twisted mass reweighting and the rational approximation for the strange quark, whereas the main feature of the simulation strategy is the approach to the physical point along a trajectory of constant trace...Go to contribution page
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Mrs Ekaterina Mastropas (College of William and Mary)23/06/2014, 16:30TalkWe present a lattice QCD calculation of the ratios of decay constants of the excited states of the pion, to that of the pion ground state. We use an anisotropic clover fermion action with three flavors of quarks, and study the pion decay constants at three values of the light-quark masses, corresponding to pion masses of 391, 524 and 702 MeV. We find that the decay constant of the first...Go to contribution page
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Masanori Hanada (Stanford/Kyoto)23/06/2014, 16:30In the gauge/gravity duality, the deconfinement transition in the gauge theory is identified with a formation of black hole in the dual gravity theory. In this talk, firstly we give quantitative evidence for this identification from the thermodynamic study of the supersymmetric theory. Then we consider generic gauge theories, including QCD, and show that the deconfinement transition is the...Go to contribution page
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Dr Szabolcs Borsanyi (Bergische Universität Wuppertal)23/06/2014, 16:30We present the continuum extrapolated kurtosis, skewness and variance of the electric charge in a grand canonical ensemble with zero or small chemical potential. This observable his a particular relevance in Heavy Ion Physics since ratios of such fluctuations have been measured in experiment at the chemical freeze-out. We discuss how lattice results describe the STAR fluctuation data at...Go to contribution page
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Dr Julius Kuti (U.C. San Diego)23/06/2014, 16:30We will use the minimal composite Higgs model to discuss theoretically and phenomenologically important issues imposed on the low mass near-conformal composite scalar of BSM Higgs physics.Go to contribution page
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Dr M Clark (NVIDIA)23/06/2014, 16:50There has been much progress to date in developing scalable sparse linear solver algorithms on GPUs, utilizing well-known mathematical methods such as mixed precision, domain decomposition and pipelining to improve performance, allowing efficient use of large GPU installations such as Blue Waters and Titan. However, there has been less focus on deploying 'mathematically optimal' linear...Go to contribution page
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Tereza Mendes (University of Sao Paulo)23/06/2014, 16:50We investigate the critical behavior of electric and magnetic gluon propagators around the deconfinement temperature of SU(2) gauge theory on large lattices, employing Landau gauge. In particular, we study the analytic properties of these propagators using several trial fitting functions.Go to contribution page
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Dr Andrew Lytle (TIFR)23/06/2014, 16:50We present results of our continuing study on mixed-action hadron spectra and decay constants using overlap valence quarks on MILC's 2+1+1 flavor HISQ gauge configurations. This study is carried out on three lattice spacings, with charm and strange masses tuned to their physical values, and with m_l/m_s = 1/5. I will discuss a determination of the mixed-action parameter Delta_mix, which enters...Go to contribution page
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Dr Christopher Kelly (Brookhaven National Laboratory)23/06/2014, 16:50The RBC & UKQCD collaborations have recently published lattice results for the K->pi pi decay amplitude in the I=2 channel, A_2, and improved results will be presented at this conference. In this presentation we discuss the determination of the I=0 channel amplitude, A_0. Combining this with A_2 provides epsilon', the measure of direct CP-violation in the Standard Model. In part I we provide...Go to contribution page
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Mr chik him wong (University of California, San Diego)23/06/2014, 16:50The widely discussed near-conformal gauge theory with two fermion flavors in the two index symmetric (sextet) representation of the SU(3) color gauge group is the minimal realization of the composite Higgs mechanism. A comprehensive study of flavor singlet scalar spectroscopy with Higgs quantum numbers is reported based on extended new data sets.Go to contribution page
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Prof. Heng-Tong DING (Central China Normal University)23/06/2014, 16:50Ratios of cumulants of conserved net charge fluctuations are sensitive to the degrees of freedom that are carriers of the corresponding quantum numbers in different phases of strong interaction matter. We calculate second and fourth order cumulants of net charm and strange fluctuations and their correlations with other conserved charges such as net baryon number and electric...Go to contribution page
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Prof. Brian Tiburzi (City College of New York)23/06/2014, 16:50TalkThe Rome method allows one to extract form factors using lattice computations performed strictly at zero momentum. We investigate the size of finite volume effects resulting from this method. As a test case, we focus on the pion charge radius and show how to ascertain the finite volume effect with the aid of chiral perturbation theory. The framework developed can easily be generalized to...Go to contribution page
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Dr Christian Schmidt (Universitaet Bielefeld)23/06/2014, 17:10Higher order cumulants of fluctuations of conserved charges are an important diagnostic tool for the thermodynamic properties of strong interacting matter close to freeze out at LHC energies as well as in the entire energy range covered with the beam energy scan (BES) at RHIC. We present recent progress on the calculation of conserved charge fluctuations with highly improved staggered quarks...Go to contribution page
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Dr Alexei Strelchenko (Fermilab)23/06/2014, 17:10Realization of the Incremental eigCG algorithm for solving Hermitian linear systems with multiple right hand sides on the CUDA platform is reported. In particular, we present details of implementation of the algorithm in the QUDA library. Preliminary performance results are provided.Go to contribution page
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Mr Daiqian Zhang (Columbia University)23/06/2014, 17:10In continuation of part I, I will discuss our use of all-to-all propagators in order to construct pi-pi operators with reduced coupling to the vacuum, which helps to reduce the noise in the K->pipi(I=0) decay amplitude. I will also present preliminary results for the pipi(I=0) phase shift, decay amplitude A_0, both with physical kinematics. The precise value of A_0, once computed, will provide...Go to contribution page
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Prof. Christian Fischer (JLU Giessen)23/06/2014, 17:10I will give an overview on our recent results for the phase diagram of QCD with Nf=2+1 and Nf=2+1+1 flavors. We use a combination of lattice and Dyson-Schwinger methods to determine the chiral and deconfinement order parameters at finite temperature and chemical potential. We find a critical end-point at large chemical potential in the vicinity of the chiral critical line extrapolated...Go to contribution page
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Prof. Keh-Fei Liu (University of Kentucky)23/06/2014, 17:10We report our calculation of the pi N sigma term and scalar form factor from the overlap fermion on 2+1 flavor domain wall fermion configurations on the 24^3 x 64 lattice at the sea quark mass which corresponds to the pion mass at 330 MeV. The improvement of the nucleon propagator and the quark loop with low mode average will be discussed.Go to contribution page
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Dr Padmanath Madanagopalan (Institute of Physics, University of Graz)23/06/2014, 17:10We present the ground and excited state spectra of triply, doubly and singly-charmed baryons by using dynamical lattice QCD. A large set of baryonic operators that respect the symmetries of the lattice and are obtained after subduction from their continuum analogues are utilized. Using novel computational techniques correlation functions of these operators are generated and the variational...Go to contribution page
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Dr Enrico Rinaldi (Physics Division, Lawrence Livermore National Laboratory)23/06/2014, 17:10Composite Higgs dynamics due to a new gauge sector has recently attracted renewed interest both phenomenologically and on the lattice. In fact, while a scalar particle consistent with the Standard Model Higgs has been discovered at the LHC, the detailed nature of this particle remains unknown. One popular description is that the Higgs is a result of a strongly coupled composite framework, such...Go to contribution page
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Dr Justin Foley (Microway and Nvidia)23/06/2014, 17:30We describe recent additions to the QUDA software library that are aimed at extending strong scaling in multi-GPU lattice calculations. These include the addition of CPU-thread support in order to increase concurrency and improve the overlap of computation and communication in Krylov solver routines, as well as the modifications needed to enable the GPUDirect RDMA feature recently...Go to contribution page
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Mr Terukazu Ichihara (Yukawa Institute for Theoretical Physics and Kyoto University)23/06/2014, 17:30We investigate QCD phase diagram at strong coupling based on strong coupling expansion in auxiliary field Monte-Carlo (AFMC) method. The strong coupling expansion is one of the ways to reduce the sign problem since the effective action is described in hadronic degrees of freedom via analytic integration over link variables. We have found that hadron phase is compressed (extended) at low...Go to contribution page
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Dr Daniel Mohler (Fermilab)23/06/2014, 17:30We present results for the mass splittings of low-lying charmonium states from a calculation of Wilson clover quarks with the Fermilab interpretation on an asqtad sea. We use five lattice spacings and two values of the light sea quarks to extrapolate our results to the physical point. Sources of systematic uncertainty in our calculation are discussed and we compare our results for the 1S...Go to contribution page
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Mr Junichi Takahashi (Kyushu University)23/06/2014, 17:30We evaluate quark number densities at imaginary chemical potential by doing lattice QCD calculations on an 8^2*16*4 lattice with clover-improved Wilson quarks of two flavors. The quark number densities are extrapolated to the small real chemical potential region by assuming some function forms. The extrapolated quark number densities are consistent with those calculated at real chemical...Go to contribution page
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Dr Xu Feng (Columbia University)23/06/2014, 17:30The rare kaon decays, $K \to pi nu nu_bar$ and $K \to pi l^+ l^-$, serve as ideal probes for the observation of New Physics (NP) effects. To isolate the NP contributions successfully, one needs to control the errors for Standard Model prediction from both short- and long-distance contributions. RBC-UKQCD collaborations have performed a successful exploratory study on the calculation of the...Go to contribution page
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Mr Evan Weinberg (Boston University)23/06/2014, 17:30The light Higgs boson of the Standard Model could arise as the consequence of the weakly broken conformal symmetry in a strongly interacting gauge theory just below the conformal window. Here we present a novel idea to study the transition from conformal to confining behavior using an SU(3) gauge theory with four light and eight heavy flavors. This system interpolates between the 12 flavor...Go to contribution page
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Dr Nuno Cardoso (NCSA, University of Illinois)23/06/2014, 17:50In this work, we present the GPU implementation of the overrelaxation and steepest descent method with Fourier acceleration methods for Laudau and Coulomb gauge fixing using CUDA for SU(N) with N>2. A multi-GPU implementation of the overrelaxation method is also presented using MPI and CUDA. The GPU performance was measured on BlueWaters and compared against the gauge fixing of the CPU MILC code.Go to contribution page
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C. B. Lang (Univ. Graz)23/06/2014, 17:50We study the three D_s quantum channels J^P = 0^+, 1^+ and 2^+ where experiments have identified the charm-strange states D*_s0 (2317), D_s1(2460), D_s1(2536) near the DK and D*K thresholds, and D*_s2(2573). We consider correlation functions for sets of qbar q operators and, for J^P = 0^+, 1^+, also the DK and D*K meson-meson interpolators and determine for these cases values of the elastic...Go to contribution page
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Dr Graham Moir (University of WUppertal)23/06/2014, 17:50We present novel calculations of the mass hierarchy of the $SU(2)$ pure gauge theory on a space-time lattice with an orbifolded fifth dimension. This theory has three parameters; the gauge coupling $\beta$, the anisotropy $\gamma$, which is a measure of the ratio of the lattice spacing in the four dimensions to that in the fifth dimension, and the extent of the extra dimension $N_{5}$. Using a...Go to contribution page
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Mr Ziyuan Bai (Columbia University in the city of New York)23/06/2014, 17:50In this work, I used a $32^3 \times 64 \times 32$, 2+1 flavor domain wall lattice with Iwasaki+DSDR gauge action. The pion mass is 171 MeV and the kaon mass is 492 MeV. We implement the Glashow-Iliopoulos-Maiani (GIM) cancellation using charm quark masses of 750 MeV and 592 MeV. This is an intermediate calculation, in that we are using both a coarse lattice spacing (1/a = 1.37GeV) so we...Go to contribution page
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Prof. Rajiv Gavai (Tata Institute of Fundamental Research)23/06/2014, 17:50Quark number susceptibility on the lattice, obtained by merely adding a \mu N-term with \mu as the chemical potential and N as the conserved quark number, has a quadratic divergence in the cut-off a. We show that it is simply a faithful representation of the corresponding continuum result. While one can eliminate it in the free theory by suitably modifying the action, as is popularly done,...Go to contribution page
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Mr Masahiro Ishii (Kyushu University)23/06/2014, 17:50We analyze the pion screening mass calculated with lattice QCD, using the entanglement-PNJL (EPNJL) model. The EPNJL model well reproduces the lattice QCD result. We then predict the sigma meson screening mass with the model. The chiral symmetry restoration can be exhibited by the difference between the pi and sigma meson screening masses. After the chiral symmetry restoration, the two...Go to contribution page
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Dr Ari Hietanen (CP3-Origins, SDU)23/06/2014, 18:10We study the meson spectrum of SU(2) gauge theory with two Wilson fermions in the fundamental representation. The theory unifies both Technicolor and composite pseudo Goldstone Boson (pGB) Higgs models of electroweak symmetry breaking. We have calculated the masses of the lightest spin one vector and axial vector mesons. In addition, we have also obtained preliminary results for the mass of...Go to contribution page
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437. Conserved currents and results from 2+1f dynamical Mobius DWF simulations at the physical pointDr Peter Boyle (University of Edinburgh)23/06/2014, 18:10We discuss the construction of the almost conserved axial and exactly conserved vector currents in the Mobius generalisation of DWF at finite Ls. I then report on the status of 2+1f DWF simulations at the physical point, with a focus on the determinations of the lattice spacings, and of the pion and kaon decay constants and the Kaon bag parameter in the continuum limit.Go to contribution page
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Mr Tomomi Sato (The Graduate University for Advanced Studies)23/06/2014, 18:10Motivated by recent arguments on effective restoration of UA(1) symmetry around the critical temperature in two-flavor QCD, we investigate the renormalization group flow of the U(2)xU(2) linear sigma model (LSM) with the traditional epsilon expansion. Introducing the UA(1) violation, the attractive basin falling into the O(4) LSM in the parameter space and its dependence on the size of UA(1)...Go to contribution page
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Ms Ruizi Li (Indiana University)23/06/2014, 18:10The conjugate gradient algorithm is among the most essential and time consuming parts of lattice calculations with staggered quarks. We test the performance of dslash, the key step in the CG algorithm, on the Intel Xeon Phi, also known as the many integrated cores (MIC) architecture, with different parallelization strategies using MPI,OpenMP, and the vector processing units (VPUs).Go to contribution page
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Dr Wolfgang Unger (University Frankfurt)23/06/2014, 18:10We compare the combinatorics of staggered and Wilson fermions in the strong coupling limit for various colors and flavors. Based on the hopping parameter expansion, we express the partition functions of both discretizations in terms of polynomials with coefficients of distinct combinatorical interpretation. We address how gauge corrections to the strong coupling limit modify the...Go to contribution page
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Mr David Murphy (Columbia University)23/06/2014, 18:10We present an update on the RBC/UKQCD collaboration’s calculation of the kaon semileptonic form factor at zero momentum transfer, $f_{+}^{K \pi}(0)$. This calculation utilizes two new $N_{f} = 2+1$ M\"{o}bius Domain Wall Fermion ensembles which allow us to simulate QCD directly at physical pion mass for the first time. Together with our previous results we now have a complete set of...Go to contribution page
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Prof. Nicolas Garron (Trinity College Dublin)24/06/2014, 09:00Talk
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Dr Stephan Durr (Wuppertal University / Juelich Forschungszentrum)24/06/2014, 09:45Talk
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Prof. Andreas Frommer (University of Wuppertal)24/06/2014, 10:15Talk
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Dr Raul Briceno (JLab)24/06/2014, 11:15TalkFew-body hadronic observables play an essential role in a wide number of processes relevant for both particle and nuclear physics. In order for Lattice QCD to offer insight into the interpretation of few-body states, a theoretical infrastructure must be developed to map Euclidean-time correlation functions to the desired Minkowski-time few-body observables. In this talk, I will first review...Go to contribution page
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Dr Takeshi Yamazaki (KMI-Nagoya)24/06/2014, 11:45Talk
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Dr Pol Vilaseca Mainar (Instituto Nazionale di FIsica Nucleare)24/06/2014, 14:15The chirally rotated Schrödinger functional renders the mechanism of automatic O(a) improvement compatible with the Schrödinger functional (SF) formulation. We here report on the determination to 1-loop order in perturbation theory of the renormalization coefficients necessary to achieve automatic O(a) improvement and the boundary improvement coefficients needed to eliminate the extra...Go to contribution page
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Mr Maxwell Hansen (University of Washington)24/06/2014, 14:15We calculate matrix elements for beyond-the-Standard-Model contributions to neutral kaon mixing from mixed-action lattice simulations with staggered sea quarks and domain-wall valence quarks. We analyze the (2+1)-flavor MILC asqtad ensembles with multiple light sea-quark masses corresponding to staggered pions as light as 220 MeV on three different lattice spacings a ~ 0.12, 0.09, and 0.06...Go to contribution page
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Dr Nigel Cundy (Seoul National University)24/06/2014, 14:15In the past few years, we have presented a new way of considering quark confinement. Through a careful choice of a Cho-Duan-Ge Abelian Decomposition, we can construct the QCD Wilson Loop in terms of an Abelian restricted field. The relationship between the QCD and restricted string tensions is exact; and we do not need to gauge fix, apply any path ordering of gauge links, or additional path...Go to contribution page
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Dr Sergey Syritsyn (RIKEN-BNL Research Center)24/06/2014, 14:15I will report initial nucleon structure results computed on lattices with 2+1 dynamical Moebius domain wall fermions at the physical point generated by RBC and UKQCD. At this stage, we evaluate only connected quark contributions. In particular, I will discuss the nucleon electric and magnetic radii, quark contributions to the nucleon spin, the nucleon axial charge, and the quark momentum...Go to contribution page
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Prof. Herbert Neuberger (Rutgers)24/06/2014, 14:15The topic of the presentation is the two-point single-eigenvalue distribution correlation function of Polyakov loops in the confined phase of four dimensional SU(N) YM theory at large N.Go to contribution page
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Prof. Stephen Sharpe (University of Washington)24/06/2014, 14:15Last year, we presented a generalization of Luescher's two-particle quantization condition to three identical, degenerate particles. While completing this work, we discovered a technical problem with our derivation which invalidated the result, in the sense that not all finite-volume corrections that fall as powers of the box size were controlled. We have found a fix to this problem,...Go to contribution page
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Mr Lukas Varnhorst (Bergische Universität Wuppertal)24/06/2014, 14:15We present preliminary results for the determination of the critical endpoint of the chiral transition in N_f=3 QCD with mu=0 at small N_t. We have employed an unimproved Wilson gauge action with staggered fermions, for which previous results on the critical endpoint are available. As an extension of these results we have studied the dependence of the critical mass on the strength of the smearing.Go to contribution page
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Mr Mattia Dalla Brida (Trinity College Dublin)24/06/2014, 14:35The chirally rotated Schrödinger functional for Wilson quarks allows for finite-volume, mass-independent renormalization schemes compatible with automatic O(a)-improvement. So far, in QCD, the setup has only been studied in the quenched approximation. Here we present first results for Nf=2 dynamical flavors for several renormalization factors of quark bilinears. We discuss how such...Go to contribution page
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Dr Andrea Shindler (Forschungszentrum Jülich)24/06/2014, 14:35With the gradient flow, we propose to calculate the QCD component of key beyond the Standard Model (BSM) matrix elements related to quark and strong theta-CP violations and the strange scalar content within the nucleon. The former set of matrix elements impacts our understanding of Electric Dipole Moments (EDMs) of nucleons and nuclei (a key signature of BSM physics), while the latter...Go to contribution page
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Prof. Ivan Horvath (University of Kentucky)24/06/2014, 14:35We examine the feasibility of the proposition that in Nf=0 QCD there is a temperature range (T_c < T < T_ch) where real Polyakov line (deconfined) vacuum exhibits valence spontaneous chiral symetry breaking and dynamical chiral polarization of Dirac eigenmodes.Go to contribution page
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Mr Christian Wiese (DESY, Zeuthen)24/06/2014, 14:35TalkWe report on the ongoing calculations of the European Twisten Mass Collaboration concerning the non-perturbative study of hadron structure. We discuss the status of these computations at the examples of various moments of parton distribution functions and give an update about the calculations for x_g and the full quark PDF of the nucleon.Go to contribution page
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Mr Mattia Bruno (DESY, Zeuthen)24/06/2014, 14:35We discuss methods to extract decay constants, meson masses and gluonic observables in the presence of open boundary conditions. Our CLS ensembles have 2+1 flavours of O(a)-improved Wilson fermions and are generated with a small twisted mass as proposed by Luescher and Palombi. We analyse the associated reweighting for different observables.Go to contribution page
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Liam Keegan (CERN)24/06/2014, 14:35We measure the running of the twisted gradient flow coupling in the Twisted Eguchi-Kawai (TEK) model, the SU(N) gauge theory on a single site lattice with twisted boundary conditions in the large N limit.Go to contribution page
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Dr Yoshifumi Nakamura (RIKEN Advanced Institute for Computational Science)24/06/2014, 14:35We present preliminary results on the critical endpoint of three flavor QCD at zero chemical potential. We employ the renormalization-group improved Iwasaki gauge action and $O(a)$-improved Wilson fermion action. The critical endpoint is determined by using the intersection points of kurtosis for mixed observable as well as plaquette, gange action density, Polyakov loop and "chiral...Go to contribution page
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Nathan Brown (Washington University in St. Louis)24/06/2014, 14:55We present a final analysis of gradient flow and the associated scale $w_0$ measured on the $N_f=2+1+1$ HISQ ensembles. Compared to previously reported results, we have improved the interpolation to physical quark masses using chiral perturbation theory, adjusted for variations in charm quark mass between ensembles, and derived a `prediction' function for estimating the scale using $w_0/a$ on...Go to contribution page
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Prof. Edward Shuryak (Stony Brook)24/06/2014, 14:55QCD topology -- mostly instantons -- had been used in the past to explain near-zero Dirac states and chiral symmetry breaking. At $T \sim T_c$ instanton are known to get decomposed into $N_c$ instanton-dyons. Several lattice observation were naturally explained by instanton-dyons. Their partition function is now numerically generated: the statistical ensemble is then used to get spectrum of...Go to contribution page
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Dr Mauro Papinutto (Universita "La Sapienza" and INFN Sez. di Roma)24/06/2014, 14:55We present preliminary results of a non-perturbative study of the scale-dependent renormalization constants of a complete basis of Delta F=2 parity-odd four-fermion operators that enter the computation of hadronic B-parameters within the SM and beyond. We consider non-perturbatively O(a) improved Wilson fermions and our gauge configurations contain two flavors of massless sea quarks. The...Go to contribution page
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Prof. Gunnar Bali (University of Regensburg)24/06/2014, 14:55TalkWe determine singlet and non-singlet hadron structure matrix elements for the nucleon and the pion from n_f=2 simulations at the physical quark mass.Go to contribution page
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Xiao-Yong Jin (RIKEN Advanced Institute for Computational Science)24/06/2014, 14:55We investigate screening masses at finite temperatures with 3 flavors using the non-perturbatively improved clover fermion action and the Iwasaki gauge action. This report focuses on the behavior of the scalar singlet correlator near the thermal critical point. I will explain the technique used to extract the correlator and discuss our preliminary results from ensembles at Nt=8.Go to contribution page
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Prof. Antonio Gonzalez-Arroyo (Instituto de Fisica Teorica UAM/CSIC)24/06/2014, 14:55We present the results of our direct precision test of volume independence for SU(N) Yang-Mills theory on the lattice with Wilson action. Wilson loop expectation values at large N are obtained by extrapolation and its finite volume dependence examined for different boundary conditions.Go to contribution page
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Dr Shinji TAKEDA (Kanazawa University)24/06/2014, 15:15We investigate a presence of critical end point in finite density/temperature QCD with three-degenerated Wilson-Clover quarks. The critical end point is estimated by the kurtosis intersection method and a gap of transition points between two independent observables. We also discuss slope/curvature of the critical end line extending from the zero density point whose details will be given in a...Go to contribution page
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Dr yibo yang (University of Kentucky)24/06/2014, 15:15Based on the lattice simulation with overlap fermions on 2+1 DWF fermion configurations on the 24^3 x 64 lattice, we carry out the first lattice QCD calculation of the quark and glue contributions to pseudoscalar and vector mesons and the nucleon. The quark mass term contributes about 50% to the mass of the light pseudoscalar mesons; whereas, it is not important in the masses of light vector...Go to contribution page
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Dr Jochen Heitger (University of Muenster)24/06/2014, 15:15We present the results of a non-perturbative determination of the improvement coefficient c_A of the axial vector current in three-flavour lattice QCD with O(a) improved Wilson quarks and tree-level Symanzik improved gauge action. Our computation involves an improvement condition which is imposed at a constant physical volume of about 1.2 fm and employs the PCAC relation in the Schrödinger...Go to contribution page
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Mr Daniel August (friedrich schiller universität jena)24/06/2014, 15:15The numerical calculation of the fermion determinant is one of the most costly computational tasks in lattice QCD. For massless two-color QCD in two dimensions we are able to calculate the fermion determinant analytically, allowing us to obtain high precision results for the mass spectrum of the theory. In the talk we review our lattice formulation in terms of purely bosonic variables...Go to contribution page
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Dr Hana Saito (DESY Zeuthen)24/06/2014, 15:15Tensor network methods form a family of efficient techniques of approximating quantum states. Their successes in quantum many-body physics have inspired their use for lattice gauge theories. We employed one of the tensor network techniques, called Matrix Product States, to investigate the Schwinger model in the Hamiltonian formulation. In this talk, we show our results for the temperature...Go to contribution page
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Dr Yuya Shimizu (RIKEN)24/06/2014, 15:35The tensor renormalization group is one of the successful methods to tackle systems whose action is complex, though the practical calculations in higher dimensions is beyond the reach of current computer facilities. The Grassmann tensor renormalization group is a generalization to systems including fermions. As a pilot study toward lattice QCD, we apply it to two-dimensional lattice QED and...Go to contribution page
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Mr Christian Wittemeier (Westfälische Wilhelms-Universität Münster)24/06/2014, 15:35We report on a non-perturbative computation of the renormalization factor Z_A of the axial vector current in three-flavour O(a) improved lattice QCD with Wilson quarks and tree-level Symanzik improved gauge action. Our normalization condition is formulated at constant physics in the same Schrödinger functional setup as is being used for the determination of the improvement coefficient c_A. It...Go to contribution page
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Dr Takumi Iritani (High Energy Accelerator Research Organization (KEK))24/06/2014, 15:35The presence of color source may modify the chiral condensate that characterizes the spontaneous breaking of chiral symmetry in the QCD vacuum. Using the overlap-Dirac eigenmodes, we investigate this phenomenon around static color sources representing quark-antiquark and three-quark systems. We show that the chiral condensate is reduced inside the flux-tube that is formed between the color...Go to contribution page
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Dr Ming Gong (Institute of High Energy Physics, Chinese Academy of Sciences)24/06/2014, 15:35The disconnected insertion part of the quark contributions to the nucleon spin are calculated with overlap fermion on DWF configurations. This work is done by calculating the disconnected three point correlation functions through the anomalous Ward identity. The quark loop of the pseudoscalar density is calculated with low-mode average and grid-noise estimate for the high modes. The overlap...Go to contribution page
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Mr Ben Galloway (University of Glasgow)24/06/2014, 15:35The system of charmonium has several excited states below the energy threshold for decay into D and Dbar mesons, which can in principle be studied accurately in lattice QCD. Studies that include many states in the spectrum have typically only been done at one value of the lattice spacing and with light quarks in the sea. Here we give results for radial and orbital excitation energies for...Go to contribution page
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Dr Balint Toth (University of Wuppertal)24/06/2014, 15:35The finite temperature transition of QCD with three degenerate flavors is expected to become a first order phase transition at small quark masses. It has been observed that introducing a sufficiently large imaginary chemical potential broadens the first order region and raises the critical quark mass to the numerically feasible regime. We report on our search for this first order transition at...Go to contribution page
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Dr Stefan Meinel (Massachusetts Institute of Technology)24/06/2014, 16:30TalkWe present results for the disconnected contributions to light-quark nucleon form factors and generalized form factors at a pion mass of approximately 300 MeV. The calculations are performed with clover fermions in a large volume, and the disconnected quark loops are evaluated using the hierarchical probing method. We compare the behavior of hierarchical probing with the traditional noise...Go to contribution page
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Dr Yusuke Taniguchi (University of Tsukuba)24/06/2014, 16:30The canonical partition function is related to the grand canonical one through the fugacity expansion. In this talk we perform the fugacity expansion by a method of the hopping parameter expansion in temporal direction: winding number expansion. Since the convergence of our expansion is good only for a small $\kappa$ we concentrate on heavy quark mass region. For a numerical simulation...Go to contribution page
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Dr Martin Schaden (Rutgers University)24/06/2014, 16:30I discuss the discretization of causal space-times on a topological lattice of events with hypercubic coordination whose links are light-like. Conditions that ensure this lattice is the discretization of a causal manifold are derived. They are encoded by a local topological lattice theory which has a particularly simple and appealing form when null-coframes are represented by spinors.Go to contribution page
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Prof. Michael Ogilvie (Washington University)24/06/2014, 16:30Recent results applying resurgence theory to finite-temperature field theories yield a detailed analytic structure determined by topological excitations. We examine finite-temperature SU(N) lattice gauge theories in light of these results. Double-trace Polyakov loop deformations move through different regions of the confined phase characterized by continuous change in the adjoint Polyakov...Go to contribution page
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Robert Mawhinney (Columbia University)24/06/2014, 16:30The RBC and UKQCD Collaborations are generating 2+1+1 flavor Mobius domain wall fermion configurations with $1/a = 3$ and 4 GeV. To achieve good topological tunneling at these weaker couplings, the gauge action is the Wilson action plus a Dislocation Enhancing Determinant (DED) term. The DED term enhances the probability of gauge fields where toplogy-changing dislocations are present,...Go to contribution page
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Dr Savvas Zafeiropoulos (LPC Universite Blaise Pascal CNRS)24/06/2014, 16:30We summarize recent non-perturbative results obtained for renormalization constants computed in the RI’-MOM scheme for $N_{\rm f}=2+1+1$ twisted mass QCD. Our implementation employs the Iwasaki gauge action and four dynamical degenerate twisted mass fermions. Renormalization constants for scalar, pseudo-scalar, vector and axial operators, as well as for the quark propagator, are computed at...Go to contribution page
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Mr Lorenzo Bongiovanni (Swansea University)24/06/2014, 16:50Recently progress has been made in applying complex Langevin dynamics to nonabelian gauge theories with a sign problem. Here we study the SU(3) gauge theory with a theta therm and present results at real theta.Go to contribution page
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Dr Akihiro Shibata (KEK)24/06/2014, 16:50We have proposed the non-Abelian dual super conductivity in SU(3) Yang-Mills (YM) theory for the mechanism of quark confinement, and by using the proposed gauge link decomposition to extract magnetic monopole in the gauge invariant way we presented the evidences in lattice conferences. In this talk, we focus on the dual Meissner effects in view of the magnetic monopole in SU(3)...Go to contribution page
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Dr Julien Frison (University of Edinburgh)24/06/2014, 16:50While Non-Perturbative Renormalisation by itself can be done at any scale, converting it to a perturbative scheme introduces a systematic error decreasing with the scale. In the case of the B_K four quark operator, this is now the dominant error on the MSbar result at 3 GeV. Increasing this scale requires both the access to finer lattices and a correct treatment of the charm effects. We will...Go to contribution page
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Dr Alejandro Vaquero (The Cyprus Institute)24/06/2014, 16:50TalkWe present results for $N_f=2+1+1$ twisted mass fermions on the disconnected contributions to the three point functions entering in studies of hadron structure. Emphasis is given to the nucleon sigma-terms, isoscalar axial charge and first moments of parton distributions for a range of pions masses. The computations are performed using QUDA code implemented on GPUs.Go to contribution page
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Prof. Derek Leinweber (University of Adelaide)24/06/2014, 16:50For almost 50 years the structure of the Lambda(1405) resonance has been a mystery for particle physicists. Even though it contains a heavy strange quark and has odd parity its mass is lower than any other excited spin-1/2 baryon. Before the existence of quarks was confirmed, Dalitz and co-workers speculated that it might be a molecular state of an anti-kaon bound to a nucleon. Although the...Go to contribution page
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Prof. Ulli Wolff (Humboldt University, Berlin)24/06/2014, 16:50We define a finite size renormalization scheme for $\phi^4$ theory which in the thermodynamic limit reduces to the standard scheme used in the broken phase. We use it to re-investigate the question of triviality for the four dimensional infinite bare coupling (Ising) limit. The relevant observables all rely on two-point functions and are very suitable for a precise estimation with the...Go to contribution page
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Dr Boram Yoon (Los Alamos National Laboratory)24/06/2014, 17:10TalkWe calculate the disconnected contribution to the nucleon isoscalar charges of the scalar, axial and tensor channels of light quarks. The calculation has been done by using the Clover valence quarks on the MILC N_f=2+1+1 HISQ lattice at a lattice spacing of 0.12 fm and light quark mass corresponding to the pion mass of 310 MeV. Two-point correlators are evaluated from 60 sources distributed in...Go to contribution page
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Mr Benjamin Jaeger (Swansea University)24/06/2014, 17:10Simulations with a finite chemical potential typically lead to a severe sign problem, prohibiting any standard Monte Carlo approach. For simulations of QCD we use the complex Langevin method, for which we apply adaptive step-sizes and gauge cooling to ensure the convergence. We present preliminary results for heavy quark QCD and explore the application for two dynamical quarks.Go to contribution page
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Zhaofeng Liu (Institute of High Energy Physics)24/06/2014, 17:10Two point functions of diquarks are calculated in the Landau gauge on the lattice with overlap fermions on 2+1-flavor domain wall fermion configurations. Masses of diquarks with spin 0 and 1 in the color anti-triplet representation are extracted. Pion mass dependence of the mass difference between the bad and good diquarks are studied.Go to contribution page
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andre walker-loud (W&M)24/06/2014, 17:10We derive a model-independent expression for finite-volume matrix elements. Specifically, we present a relativistic, non-perturbative analysis of the matrix element of an external current between a one-scalar in-state and a two-scalar out-state. Our result, which is valid for energies below higher-particle inelastic thresholds, generalizes the Lellouch-Luscher formula in two ways: we allow the...Go to contribution page
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Mr Jangho Kim (Seoul National University)24/06/2014, 17:10We present matching factors for the four-fermion operators obtained using the non-perturbative renormalization method (NPR) in RI-MOM scheme for improved staggered fermions on the MILC asqtad lattice (N_f = 2+1). Using 20^3 * 64 lattice (a = 0.12 fm, am_l/am_s = 0.01/0.05), we obtain the matching factor of B_K operator. Also we are in the middle of data analysis on the BSM...Go to contribution page
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Dr Masayasu Hasegawa (Bogoliubov Laboratory of Theoretical Physics, JINR)24/06/2014, 17:10Monopoles are considered that play the very important roles for the color confinement mechanism. University of Kanazawa and Pisa groups have shown a number of studies which support the confinement mechanism due to monopole condensations by the lattice simulations. Instantons that are other topological objects found as solutions of QCD. The close relations to chiral symmetry breaking are...Go to contribution page
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Dr Bastian Brandt (University of Regensburg)24/06/2014, 17:30We investigate an alternative lattice discretization of continuum SU(Nc) Yang-Mills theory in which the self-interactions of the gauge field are induced by a path integral over Nc auxiliary bosonic fields which are coupled linearly to the gauge field. In two dimensions there exists an analytic proof that the new discretization reproduces Yang-Mills theory in its non-perturbative continuum...Go to contribution page
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Mr Masaaki Tomii (Graduate university for advanced studies)24/06/2014, 17:30We study a non-perturbative determination of the renormalization constants of flavor non-singlet quark bilinear operators. The renormalization condition is imposed on correlation functions of bilinear operators in the coordinate space. The results are converted to the value in the MSbar scheme by a perturbative matching. The calculation is done on gauge configurations generated with the Mobius...Go to contribution page
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Mr Dean Howarth (Rensselaer Polytechnic Institute)24/06/2014, 17:30We describe our studies of multi-pion correlation functions computed using stochastic propagators in quenched lattice QCD, harnessing GPUs for acceleration. We find that projecting onto momentum states for the pions becomes enormously expensive and has a poor scaling with the linear extent of the lattice. It is also found that correlations between stochastic propagators appearing in the same...Go to contribution page
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Dr Eduardo Follana Adin (Universidad de Zaragoza)24/06/2014, 17:30We investigate numerically the spectral flow introduced by Adams for the staggered Dirac operator on realistic quenched gauge configurations in 2D and 4D. We study both the unimproved and the HISQ Dirac operators, and we compare with the case of spectral flow for Wilson fermions. We show that the spectral flow provides a good topological definition of the index, with a clear separation of high...Go to contribution page
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Mingyang Sun (University of Kentucky)24/06/2014, 17:30TalkWe present a calculation of $\langle x \rangle$ for the strange quark in the nucleon. We adopt overlap fermion action on 2 + 1 flavor domain-wall fermion configurations on the $24^3 \times 64$ lattice. Smeared grid $Z_3$ sources are deployed to calculate the nucleon two-point function with low-mode substitution. Even-odd grid sources and time-dilution technique with stochastic noises are...Go to contribution page
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Helvio Vairinhos (University of Porto)24/06/2014, 17:30We integrate out all the link variables in the partition function of SU(N) or U(N) lattice gauge theory with the Wilson plaquette action, for arbitrary values of the lattice coupling. The partition function is recast as a Gaussian integral over auxiliary fields, after using suitable Hubbard-Stratonovich transformations. We extend our formalism to lattice gauge theories with staggered fermions...Go to contribution page
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Dr Christian Torrero (Centre de Physique Théorique (CPT), Aix-Marseille Université)24/06/2014, 17:50The nucleon sigma terms are quantities that play a crucial role in phenomenology: among others, they connect the pion-nucleon and the kaon-nucleon amplitudes to the hadron spectrum and they are also relevant for the direct detection of Dark Matter (DM). We present preliminary results for these sigma terms obtained from N_f=2+1 lattice simulations that are performed at five lattice spacings...Go to contribution page
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Mr Yong-Chull Jang (Seoul National University)24/06/2014, 17:50To achieve smaller heavy-quark discretization errors, the OK action was proposed as an improvement of the Fermilab action. The OK action includes the dimension 6 and 7 operators necessary for tree-level matching to QCD through order 1/m_Q^3 for heavy-light mesons and v^6 for quarkonium. To assess the improvement, we extend previous numerical tests with heavy meson masses by analyzing data...Go to contribution page
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Mr Boye Buyens (University Ghent), Dr Karel Van Acoleyen (Ghent University)24/06/2014, 17:50We consider the matrix product state formalism for the simulation of Hamiltonian lattice gauge theories. To this end, we define matrix product states which are manifestly gauge invariant. As an application, we study 1+1 dimensional one flavor quantum electrodynamics, also known as the massive Schwinger model. We are able to determine very accurately the ground state properties and one-particle...Go to contribution page
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Prof. Francesco Knechtli (University of Wuppertal)24/06/2014, 17:50We simulate a theory with two dynamical O(a) improved Wilson quarks whose mass M is close the charm quark mass and at three values of the lattice spacing ranging from 0.066 to 0.038 fm. This theory is a prototype to study the decoupling of heavy quarks. We measure the mass and cut-off dependence of ratios of gluonic observables defined from the Wilson flow or the static potential. The...Go to contribution page
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Dr Eruzzi Giovanni (University of Parma and INFN)24/06/2014, 17:50The sign problem prevents lattice simulations of many models of physical interest. One proposal for evading such problems is the thimble regularization. I will discuss its application to the phi^4 0-dimensional integral, which is a toy model that has been studied for many years as a prototype of complex-valued action and raises several problems within a treatment via complex Langevin; this...Go to contribution page
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Prof. Thacker H. B. (University of Virginia)24/06/2014, 17:50There is considerable evidence, based on large $N_c$ chiral dynamics, holographic QCD, and Monte Carlo studies, that the topological structure of the QCD vacuum consists of discrete quasivacua separated by domain walls across which the local value of the topological $\theta$ parameter jumps by $\pm2\pi$. Topological insulators are condensed matter systems which are bulk insulators with...Go to contribution page
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Dr Hyung-Jin Kim (Brookhaven National Laboratory)24/06/2014, 18:10The $\eta-\eta'$ mass splitting coming from anomalous effect on U(1) axial currents has been a historical issue. % The QCD gauge field topology with instanton can explain this problem and show consistent result with experimental mass of $\eta'$. % Based on the $2+1$ flavor lattice QCD simulation, previous $\eta-\eta'$ masses study shows about 15\% level of accuracy. % With the advanced...Go to contribution page
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Valentina Verduci (University of Graz)24/06/2014, 18:10In recent years the study of two particle systems on the lattice has led to excellent results in the meson sector of the QCD spectrum, however baryon resonances remain mostly unexplored. We present an initial study of pion-nucleon systems as decay product of baryon resonances in different channels. The final goal is to extract the resonance parameters from the correlation functions of...Go to contribution page
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Mr Jaehoon Leem (Seoul National University)24/06/2014, 18:10We present results of the Kaon B-parameters calculated using the HYP-improved staggered quarks on the MILC asqtad lattices. The perturbative matching is done at one-loop level. We extrapolate the data to physical pion mass using the SU(2) staggered chiral perturbation theory. After that, we simultaneously extrapolate results to the continuum (a = 0) and physical sea quark mass. We...Go to contribution page
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Mr Alessandro Sciarra (Goethe University, Frankfurt am Main), Mr Christopher Pinke (Institute for Theoretical Physics, Goethe-University Frankfurt am Main)24/06/2014, 18:10In recent years it has been shown that Lattice QCD (LQCD) can benefit enormously from Graphic Processing Units (GPUs), which are well suited for memory bandwidth limited applications. Accordingly, the usage of GPUs in LQCD simulations is still expanding, mainly relying on CUDA, applicable to NVIDIA hardware only. A hardware vendor independent approach is given by the Open Computing...Go to contribution page
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Mr Alessandro Sciarra (Goethe University, Frankfurt am Main), Mr Christopher Pinke (Institute for Theoretical Physics, Goethe-University Frankfurt am Main)24/06/2014, 18:10In recent years it has been shown that Lattice QCD (LQCD) can benefit enormously from Graphic Processing Units (GPUs), which are well suited for memory bandwidth limited applications. Accordingly, the usage of GPUs in LQCD simulations is still expanding, mainly relying on CUDA, applicable to NVIDIA hardware only. A hardware vendor independent approach is given by the Open Computing Language...Go to contribution page
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Yusuke Namekawa (University of Tsukuba)24/06/2014, 18:10Comparative study of topological charge is performed. Topological charges are measured by a cloverleaf operator on smoothed gauge configurations. Various types of smoothing techniques are employed. We investigate to what extent each smoothing makes the topological charge an integer. Consistency of the topological charge in the fermionic definition is also examined.Go to contribution page
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Mr Alexander Schmidt (Phd)24/06/2014, 18:10We explore two flavor scalar electrodynamics on the lattice, which has a complex phase problem at finite chemical potential. By rewriting the action in terms of dual variables this complex phase problem can be solved exactly. The dual variables are link- and plaquette occupation numbers, subject to local constraints that have to be respected by the Monte Carlo algorithm. For the simulation we...Go to contribution page
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Dr Enrico Rinaldi (Physics Division, Lawrence Livermore National Laboratory), Yasumichi Aoki (Nagoya University)24/06/2014, 18:10PosterThe spectrum of twelve-flavor QCD has been studied in details by the LatKMI collaboration. Here we present our updated results obtained with the HISQ action at two lattice spacings, several volumes and fermion masses. We emphasize the existence of a flavor-singlet scalar state parametrically light with respect to the rest of the spectrum, first reported in our paper [1]. This feature is...Go to contribution page
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Mr Arjun Gambhir (College of William and Mary)24/06/2014, 18:10Reverse Monte Carlo, by Mak and Sharma, is a technique that allows for stochastic modification of the action of a lattice theory, while respecting the detailed balance condition of the original action. This modification of the action may permit more efficient evolution of modes with large autocorrelation times. The classic Swendsen and Wang cluster algorithm for the Ising model is in fact...Go to contribution page
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Mr Johannes Heinrich Weber (Technische Universität München)24/06/2014, 18:10The explicit breaking of time-reflection symmetry in the Karsten-Wilczek action is hidden in various mesonic correlation functions that are calculated in the quenched approximation. Two underlying discrete product symmetries are discussed, which each allow for enforcement of time-reflection symmetry for correlation functions constructed according to additional symmetry requirements. An...Go to contribution page
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Alessandro Papa (Universita` della Calabria & INFN-Cosenza)24/06/2014, 18:10Three-dimensional Z(N) lattice gauge theories are studied numerically at finite temperature for N = 5, 6, 8, 12, 13, 20 and for N_t=2,4,8. For each model the location of phase transitions and their critical indices are determined. The scaling of critical points with N is proposed. The data obtained enable us to verify the scaling near the continuum limit for the Z(N) models at finite temperatures.Go to contribution page
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Prof. Weonjong Lee (Seoul National University)24/06/2014, 18:10We present results of $\varepsilon_K$, the indirect CP violation parameter calculated on the lattice combined with various inputs from the experiments. In this analysis we use the lattice results of $B_K$ and $V_{cb}$ for the exclusive channel. In addition, we also use Wolfenstein parameters from the CKM fitters and UT fitters. We find 3.4(3) $\sigma$ difference in the exclusive...Go to contribution page
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Dr Etsuko Itou (KEK, Japan)24/06/2014, 18:10We show the numerical simulation result for the mass anomalous dimension of the SU(3) gauge theory coupled to Nf = 12 fundamental fermions. We use both the step scaling method and the hyperscaling for the Dirac eigenmode to determine the anomalous dimension in the vicinity of the infrared fixed point of the theory. The continuum extrapolation is carefully taken in both analyses. We also...Go to contribution page
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Christof Gattringer (Univ. Graz)24/06/2014, 18:10Using hopping expansion techniques we discuss a partial mapping of finite density lattice QCD to dual variables. After truncation the partition sum has only real and positive contributions also at arbitrary chemical potential, and a Monte Carlo simulation is possible. We discuss the algebraic aspects of the dualization and show some first numerical results.Go to contribution page
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Dr Eigo Shintani (Mainz University)24/06/2014, 18:10We report preliminary result of all-mode-averaging technique in Wilson fermion. On two-flavor CLS configurations, we compare the performance to obtain high precision of nucleon form factor and hadronic vacuum polarization function using truncated solver with deflated SAP+GCR algorithm.Go to contribution page
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Prof. Attilio Cucchieri (University of Sao Paulo)24/06/2014, 18:10By evaluating the so-called Bose-ghost propagator, we present the first numerical evidence of BRST-symmetry breaking in minimal Landau gauge, i.e. due to the restriction of the functional integration to the first Gribov region in the Gribov-Zwanziger approach. We find that our data are well described by a simple fitting function, which can be related to a massive gluon propagator in...Go to contribution page
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Jack Laiho (Syracuse University)24/06/2014, 18:10PosterI present the results of a study of Euclidean dynamical triangulations (EDT) in an attempt to formulate a theory of quantum gravity and to make contact with Weinberg's asymptotic safety scenario. There are two unphysical phases appearing in EDT, neither of which resembles semiclassical gravity. When the phase diagram is enlarged by including a nontrivial measure term a new region of the...Go to contribution page
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Zechariah Gelzer (University of Iowa)24/06/2014, 18:10We are studying the SU(3) gauge theory with 12 staggered fermions, searching for the endpoint of the line of first-order phase transitions in the mass-beta plane. This endpoint plays an important role in our understanding of the phase diagram of this model. Having found this endpoint with high statistics on a small lattice using unimproved staggered fermions, we are working to find it on...Go to contribution page
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Dr Konstantin Ottnad (University of Cyprus)24/06/2014, 18:10The extraction of the magnetic form factor of the nucleon at zero momentum transfer is usually performed by adopting a parametrization for its momentum dependence and fitting the results obtained at finite momenta. We present methods that rely on taking the derivative of relevant correlators to extract directly the magnetic form factor at zero momentum without the need to assume a functional...Go to contribution page
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Mr Pranjal Vachaspati (MIT)24/06/2014, 18:10In recent work, it has been shown that contractions for multi-nucleon systems can be cast in terms of weighted sums of determinants of matrices constructed from quark propagators. For typical correlation functions even for few nucleon systems, the number of such determinants can be very large depending on the complexity of the interpolating fields that are used. We investigate efficient...Go to contribution page
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Prof. Shailesh Chandrasekharan (Duke University)24/06/2014, 18:10Recent developments have shown that the fermion bag approach is a powerful method to solve fermion lattice field theories using Monte Carlo methods. Some sign problems that had remained unsolved earlier can now be solved within this approach. In this work we argue that the fermion bag approach also gives new insight into the mechanism of fermion mass generation. We discuss how chiral...Go to contribution page
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andre walker-loud (W&M)24/06/2014, 18:10Practitioners of lattice quantum chromodynamics (LQCD) have been some of the primary pioneer users of the state-of-the-art HPC systems, and contribute towards the stress tests of such new machines as soon as they become available. As with all aspects of HPC, I/O is becoming an increasingly specialized component of these systems. In order to take advantage of the latest available...Go to contribution page
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Swagato Mukherjee (BNL)24/06/2014, 18:10
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amarjit soni (BNL)24/06/2014, 18:10We report our recent study of proton and neutron decay matrix element with highly improved statistics using all-mode-averaging technique. On 2+1 flavor domain-wall fermion configurations, we obtain accurate proton to pseudoscalar (pion, K and eta) meson transition form factor. In this report we also discuss the comparison with baryon chiral perturbation in physical kinematics and estimate...Go to contribution page
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Dr Thomas Primer (University of Arizona)24/06/2014, 18:10We present calculations of the $K\to\pi,l\nu$ and $D\to\pi,l\nu$ semileptonic form factors at $q^2=0$. These form factors are important for the determination of the CKM matrix elements $\lvert{V_{us}}\rvert$ and $\lvert{V_{cd}}\rvert$ respectively. This work uses the HISQ action for both valence quarks and sea quarks on MILC $N_f=2+1+1$ configurations. We employ twisted boundary conditions...Go to contribution page
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Dr Siwei Qiu (National Institute of Health)24/06/2014, 18:10Neurophysics is a relatively new science. We will use quantum field theory to analyze the neural network of theta model. With a special lattice, one can explore the short term memory using lattice field theory calculation. Here we will theoretically show the path integral formalism which can be used to do perturbation theory. Simple lattice simulation will be conducted to compare with the...Go to contribution page
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Dr Satoru Ueda (KEK)24/06/2014, 18:10We are developing a new code set ``Bridge++'' for lattice simulations. It is aimed to be an extensible, readable, and portable workbench, while it keeps a high performance. Bridge++ covers conventional lattice actions and numerical algorithms. A recent massively parallel cluster system requires a hybrid parallel programing, such as MPI and OpenMP. We also need elaborated programing...Go to contribution page
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Dr Marcus Petschlies (Cyprus Institute / CaSToRC)24/06/2014, 18:10We present our results for the electron, the muon, and the tau anomalous magnetic moments obtained with four dynamical quarks. Performing the continuum limit and an analysis of systematic effects, full agreement with phenomenological results is seen. Additionally, the light quark contributions on the four-flavour sea are compared to the values obtained for N_f=2 physically light quarks. In...Go to contribution page
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Dr Frank Winter (Thomas Jefferson National Accelerator Facility)24/06/2014, 18:10The Low Level Virtual Machine (LLVM) compiler infrastructure is a promising platform for development of code that features performance portability across a wide variety of architectures. It's widely embraced by HPC industry and academia and high performance code generating backends are available and supported for many relevant architectures such as CUDA, X86-64, PowerPC64 including...Go to contribution page
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Mr Sourav Mondal (Indian Association for the Cultivation of Science)24/06/2014, 18:10Following the multilevel scheme we present an error reduction algorithm for extracting glueball masses from monte-carlo simulations of pure SU(3) lattice gauge theory. We look at the two lightest states viz. the 0^{++} and 2^{++}. Our method involves looking at correlations between large wilson loops and does not require any smearing of links. The error bars we obtain are at the moment...Go to contribution page
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Prof. Christine Davies (University of Glasgow)24/06/2014, 18:10HPQCD Collaboration: We will present the first lattice QCD calculation of the mixing parameters f_B\sqrt(B_B) and f_B_s\sqrt(B_B_s) for physical light quark masses. We use 2+1+1 MILC configurations at 3 values of the lattice spacing and with three u/d quark masses going down to the physical value. We use improved NRQCD for the b quarks.Go to contribution page
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Michael Wagman (University of Washington)24/06/2014, 18:10Neutron-antineutron oscillation is a baryon number violating process that is predicted to occur in many theories of physics beyond the standard model. To make quantitative predictions that can be compared to experiment, matrix elements of six-quark effective operators must be computed via lattice QCD and must also be connected to continuum beyond the standard model operators. We present...Go to contribution page
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Dr Alexander Rothkopf (Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany), Dr Peter Petreczky (Brookhaven National Laboratory - Department of Physics, Upton, USA)24/06/2014, 18:10We present the results of a recent study on the in-medium modification of the spectral properties of Bottomonium S-wave (\Upsilon) and P-wave (\chi_b) states. The medium degrees of freedom are represented by 48^3x12 HotQCD lattices with Nf=2+1 light HISQ flavors, which span the temperature range 140.40(MeV)(= 0.911T_C) < T < 248.63(MeV)(= 1.614T_C). The heavy quarks on the other hand are...Go to contribution page
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Dr Piotr Korcyl (DESY Zeuthen)24/06/2014, 18:10We report on our non-perturbative investigations of Supersymmetric Yang-Mills Quantum Mechanics with four supercharges. We employed two independent numerical methods. As a first method we used the cut Fock space approach in which one constructs the Hamiltonian matrix in an approximated basis of the Hilbert space and diagonalize it numerically to obtain the energy spectrum. As a second method...Go to contribution page
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Mr Jeonghwan Pak (Seoul National University)24/06/2014, 18:10There are new NVIDIA technologies, such as direct parallelism and GPU Direct, which reduce the communication time between GPUs and CPUs. NVIDIA Kepler GPUs also provide new features to improve the memory usage of CUDA codes which allows better performance in memory access, memory allocation, and deallocation. We optimize our conjugate gradient code for staggered quarks to obtain the full...Go to contribution page
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Dr Markus Pak (University of Graz)24/06/2014, 18:10The chirally symmetric Overlap quark propagator is explored for the first time in Coulomb gauge. This gauge is well suited for studying the relation between confinement and chiral symmetry breaking. The dressing functions of the quark propagator and the dynamical mass function are evaluated. Chiral symmetry is then artificially restored by removing the low eigenmodes from the Dirac operator....Go to contribution page
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Dr Michael Creutz (Physics Department, BNL)24/06/2014, 18:10Partially quenched chiral perturbation theory usually assumes that valence quarks propagating on gauge configurations prepared with sea quarks of different masses will form a chiral condensate as the valence quark mass goes to zero. I present a counterexample involving non-degenerate sea quarks where the valence condensate does not form.Go to contribution page
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Mr Marios Costa (University of Cyprus)24/06/2014, 18:10The chromomagnetic operator mixes with a large number of operators under renormalization. We identify which operators can mix with the chromomagnetic operator, at the quantum level. Even in dimensional regularization (DR), which has the simplest mixing pattern, the chromomagnetic operator mixes with a total of 9 other operators,forming a basis of dimension-five (d=5), Lorentz scalar operators...Go to contribution page
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Mr Alessandro Amato (Swansea University)24/06/2014, 18:10The properties of the ground state of two-color QCD at non-zero baryon chemical potential mu present an interesting problem in strongly-interacting gauge theory; in particular the nature of the physically-relevant degrees of freedom in the superfluid phase in the high-mu regime still needs clarification. In this study we present evidence for in-medium effects at high mu by studying the wave...Go to contribution page
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Dr Shinji Ejiri (Niigata University)24/06/2014, 18:10We investigate the phase transitions of (2+Nf)-flavor QCD, where two light flavors and Nf massive flavors exist, to discuss the electroweak baryogenesis in realistic technicolor scenario. Because an appearance of a first order phase transition at finite temperature is a necessary condition for the baryogenesis, it is important to study the nature of phase transition in the case of massless 2...Go to contribution page
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Dr Christopher Monahan (College of William and Mary), Kostas Orginos (College of William and Mary / JLab)24/06/2014, 18:10Lattice QCD calculations of parton distribution functions have so far been restricted to only their first few Melin moments. Broken rotational symmetry on the lattice introduces unavoidable power divergent mixing of lattice twist-2 matrix elements of different spin that obscures the continuum limit. Here I discuss new options that either avoid power divergent mixing or allow us to perform...Go to contribution page
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Ms Olga Larina (Institute of Theoretical and Experimental Physics)24/06/2014, 18:10We calculated correlators of vector and pseudoscalar currents in external strong abelian magnetic field in SU(3) gluodynamics. The masses of charged and neutral mesons with various spins were calculated. We found out that the masses of mesons with zero spin s=0 decreased in increasing magnetic field, but the masses of Rho mesons with nonzero spin increased in the field.Go to contribution page
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Mr Thomas Kloiber (University of Graz)24/06/2014, 18:10We study the effect of the theta angle in two dimensional scalar QED. Since the theta term is purely imaginary, it introduces a complex action problem which prevents conventional numerical simulations at non-zero values of theta. This problem is solved by mapping the model to a dual representation, which is real and non-negative, hence suitable for Monte Carlo simulations. We present technical...Go to contribution page
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Oliver Witzel (Boston University)24/06/2014, 18:10In order to study the transition from conformal to confining behavior of an SU(3) gauge theory, we present the novel idea to simulate a theory with four light and eight heavy flavors. Varying the mass of the heavy flavors, the theory changes from conformal to confining allowing us to demonstrate the walking nature of the running coupling as a function of the mass of the eight heavier flavors.Go to contribution page
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Dr Matthew Wingate (DAMTP, University of Cambridge)24/06/2014, 18:10This poster reviews our recent calculation of $B \to K^*$, $B_s \to \phi$, and $B_s \to K^*$ form factors using nonrelativistic heavy quarks and improved staggered quarks on MILC lattices. These unquenched calculations, performed in the low-recoil kinematic regime, provide a significant improvement over the use of extrapolated light cone sum rule results. We use the form factors along...Go to contribution page
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Dr Ydalia Delgado Mercado (University of Graz)24/06/2014, 18:10We use the density of states method to compute the observables of the effective center model of QCD at finite density (where the system suffers from a complex phase problem). The density of states method is a reweighting method based on an improved evaluation of histograms for the distribution of states. We test this approach against the results from the dual simulations of the model, where...Go to contribution page
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Prof. Carleton DeTar (University of Utah)24/06/2014, 18:10We present preliminary simulation results for the I = 0 charmonium state X(3872)(1++) and the I = 1 charmonium state Zc(3900)(1+-). The study is performed on (2+1+1)-flavor highly improved staggered quark (HISQ) lattices with clover (Fermilab interpretation) charm quarks and HISQ light quarks. Since the X(3872) lies very close to the open charm D-bar-D* threshold, we use a combination of...Go to contribution page
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Alexei Bazavov (University of California/University of Iowa)24/06/2014, 18:10We study the U(1)-Higgs model in two dimensions in the strongly coupled regime. The goal is to generate an effective theory where link variables are integrated out, producing 4-field operators. This theory can be matched with the second-order perturbation theory effective Hamiltonian for the Bose-Hubbard model. Such correspondence can then be exploited for building a lattice gauge theory...Go to contribution page
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Prof. Gernot Münster (University of Muenster)24/06/2014, 18:10In Monte Carlo simulations of $\mathcal{N}=1$ supersymmetric Yang-Mills theory the mass of the unphysical adjoint pion, which is easily obtained numerically, is being used for the tuning to the limit of vanishing gluino mass. We show how to define the adjoint pion in the framework of partially quenched chiral perturbation theory and we derive a relation between its mass and the mass of the...Go to contribution page
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Ion-Olimpiu Stamatescu (Inst. Theor. Physik, Universitaet Heidelberg)24/06/2014, 18:10We use the heavy dense approximation of QCD (HD-QCD) at next-to-leading order (NLO) in the hopping expansion, keeping the full Yang-Mills action. We perform simulations at low temperatures, in the region below 1/3 T_c(\mu=0), and at large \mu, \mu/T above 5. We analyse the structure in the baryonic density and other quantities at the onset. We present data from reweighting (RW) and...Go to contribution page
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Dr Björn Leder (University of Wuppertal)24/06/2014, 18:10Quark mass reweighting can be used to tune the mass of dynamical quarks. The basic idea is to use gauge field ensembles generated at some bare mass parameters to evaluate observables at different bare sea quark masses. This involves the computation of so called reweighing factors which are given as ratios of fermion determinants. In the case of simulations including the strange quark,...Go to contribution page
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Dr Guido Cossu (KEK)25/06/2014, 09:00Possible (effective) restoration of the axial U(1) symmetry at finite temperature has attracted a lot of attention in the last few years thanks to the development of the chiral lattice actions and algorithmic improvements. In our previous work we utilized the overlap fermion formulation to show an evidence for a restoration of the axial symmetry above the phase transition. In this work we...Go to contribution page
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Prof. Anna Hasenfratz (University of Colorado Boulder)25/06/2014, 09:00The gradient flow renormalized coupling offers a relatively inexpensive way to calculate the step scaling function or the lattice scale, but both applications can be hindered by large lattice artifacts. Recently we introduced an empirical non-perturbative improvement that can remove O(a^2) lattice artifacts. The method is easy to implement and can be applied to any lattice gauge...Go to contribution page
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Dr Waseem Kamleh (University of Adelaide)25/06/2014, 09:00The role of 5-quark operators in extracting the nucleon excited state spectrum via correlation matrix techniques is explored. In particular, the coupling of meson-baryon operators to nucleon resonance states and scattering states is studied. Results are presented for 2+1 flavour dynamical ensembles in both the positive and negative parity channels.Go to contribution page
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Dr michele caselle (Department of Physics, Torino University)25/06/2014, 09:00One of the most interesting recent results on the effective string description of Lattice Gauge Theories is the universality of the first few terms of the effective action. This is a direct consequence of the Lorentz invariance of the underlying LGTs and makes this theory much more predictive than usual effective models in particle physics. Besides the well known Nambu-Goto action, one of...Go to contribution page
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Dr Indrakshi Raychowdhury (Institute of Mathematical Sciences, Chennai, India)25/06/2014, 09:00Within the Hamiltonian formulation of Lattice gauge theories, prepotentials, belonging to the fundamental representation of the gauge group and defined locally at each site of the lattice, enables us to construct local loop operators and loop states. Within this prepotential approach one gets mass gap analytically in some approximations in the weak coupling limit of the theory.Go to contribution page
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Prof. Jacobus Verbaarschot (Stony Brook University)25/06/2014, 09:00In a sector of fixed topological charge, the chiral condensate has a discontinuty given by the Banks-Casher formula also in the case of one-flavor QCD. However, at fixed $\theta$ angle, the chiral condensate remains constant when the quark mass crosses zero. To reconcile these contradictory observations, we have evaluated the spectral density of one-flavor QCD at $\theta=0$. For negative...Go to contribution page
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Mr Antoine Gérardin (LPT)25/06/2014, 09:00I will present results on the scalar B meson ($B_0^*$) sector using $N_f=2$ $\mathcal{O}(a)$-improved Wilson-Clover fermions and the Heavy Quark Effective Field theory at the static limit to describe the b-quark. Since the scalar B meson lies near the B $\pi$ threshold for our simulations set-up, we have implemented meson-meson as well as quark-antiquarks interpolating fields to disentangle...Go to contribution page
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Dr Tomomi Ishikawa (RIKEN BNL Research Center)25/06/2014, 09:20Neutral B meson mixing matrix elements and B meson decay constants are calculated. Static approximation is used for b quark and domain-wall fermion is employed for light quarks. The calculations are carried out on Nf=2+1 dynamical ensembles with lattice spacings of 0.086fm and 0.11fm, and a fixed physical spatial volume of about (2.7fm)^3, generated by RBC/UKQCD Collaborations. We employ two...Go to contribution page
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Dr Georg Engel (Universita' Milano-Bicocca)25/06/2014, 09:20Exploiting the Banks-Casher relation, we present a direct determination of the chiral condensate in two-flavor QCD, computing the mode number of the O(a)-improved Wilson-Dirac operator below various cutoffs. We make use of CLS-configurations with three different lattice spacings in the range of 0.05-0.08 fm and pion masses down to 190 MeV. Our data indicates a finite density of eigenmodes near...Go to contribution page
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Mr Davide Vadacchino (Università degli Studi di Torino - INFN Sezione di Torino)25/06/2014, 09:20The U(1) lattice gauge theory in three dimensions is a perfect laboratory to study the subtle properties of the confining string. On the one hand, thanks to the mapping to a coulomb gas of monopoles, the model can be exactly solved and confinement proven analytically. On the other hand high-precision numerical estimates of Polyakov loop correlators can be obtained via a duality map to a spin...Go to contribution page
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Mr Akio Tomiya (Osaka University)25/06/2014, 09:20We investigate the issue of possible restoration of the axial U(1) symmetry at finite temperature, using lattice simulations with the Mobius domain-wall fermion. In this talk, we focus on the effects of near-zero Dirac eigenmodes, which play a crucial role for both SU(2)xSU(2) chiral symmetry restoration and the restoration/breaking of axial U(1) symmetry. Performing simulations at two...Go to contribution page
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Mr Marcin Szyniszewski (Lancaster University, The University of Manchester)25/06/2014, 09:20We employ exact diagonalization with strong coupling expansion to the massless and massive Schwinger model. For the massless case, this allows us for a high accuracy continuum limit estimation of the ground state energy and scalar and vector mass gaps with precisions of the order of one part per billion or better. Furthermore, we investigate the chiral condensate and compare our calculations...Go to contribution page
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Wolfgang Soeldner (Regensburg University)25/06/2014, 09:20Based on CLS simulations with 2+1 flavors and open boundaries we present first results of the baryon spectrum. We report on the status of our effort related to these simulations and the chiral extrapolation to the physical point.Go to contribution page
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Dr Jarno Rantaharju (Riken Advanced Institute for Computational Science)25/06/2014, 09:20We present preliminary results of the gradient flow running coupling with Dirichlet boundary condition in the SU(2) gauge theory with 8 fermion flavors. Improvements to the gradient flow measurement allow us to obtain a robust continuum limit. The results are consistent with perturbative running in the weak coupling region and show slow running at strong coupling.Go to contribution page
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Oliver Witzel (Boston University)25/06/2014, 09:40We compute B-meson decay-constants and neutral B-meson mixing using relativistic b-quarks and domain-wall light quarks. We present results for fB, fBs, and their ratio including a complete systematic error budget from an analysis of five sea-quark ensembles with pion masses as light as ~290 MeV and two lattice spacings of a~0.11 and 0.08 fm. We are currently adding data at the physical pion...Go to contribution page
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Mr Christos Kallidonis (The Cyprus Institute)25/06/2014, 09:40We present results on the masses of the low lying baryons using gauge configurations with $N_f=2+1+1$ flavors of maximally twisted mass fermions. The strange and charm quark masses are tuned to their physical values. We use three values of the lattice spacing, determined from the nucleon mass. Both cut-off effects and volume effects are investigated. We demonstrate that isospin symmetry...Go to contribution page
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Prof. Tamas G. Kovacs (Institute for Nuclear Research, Debrecen)25/06/2014, 09:40Recently we found an Anderson-type localization-delocalization transition in the QCD Dirac spectrum at high temperature. Using spectral statistics we obtained a critical exponent compatible with that of the corresponding Anderson model. Here we study the spatial structure of the eigenmodes both in the localized and the transition region. Based on previous studies in the Anderson model, at the...Go to contribution page
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Francesca Cuteri (Università della Calabria, INFN-Cosenza)25/06/2014, 09:40The transverse profile of the chromoelectric field generated by a quark-antiquark pair in the SU(3) vacuum is analysed within the dual superconductor scenario, then the London penetration depth and coherence length are extracted. The color field is determined on the lattice through a connected correlator of two Polyakov loops measured on smeared configurations.Go to contribution page
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Prof. C.-J. David Lin (National Chiao-Tung University, Taiwan)25/06/2014, 09:40We present our study of the running coupling constant in SU(3) gauge theory with 12 flavours of fermions. In this work we use the method of the step scaling, implemented on lattices with twisted boundary condition. The lattice volumes in this work are 6, 8, 10, 12, 16, 20, and 24. This choice of volumes enables us to investigate the systematic effects in the continuum extrapolation. We...Go to contribution page
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Dr Elena Garcia Ramos (HU Berlin / DESY-Zeuthen)25/06/2014, 09:40We present our results for the topological susceptibility in the quenched case and attempt a non-perturbative test on the Witten-Veneziano formula. We perform a continuum limit extrapolation of the topological susceptibility computed using spectral projectors. The physical situation of the quenched ensembles was matched to the maximally twisted mass dynamical simulations used to compute the...Go to contribution page
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David Adams (Nanyang Technological University)25/06/2014, 09:40An update on our ongoing research on staggered Wilson fermions (a 2-flavor staggered version of Wilson fermions) will be given. Previously we found that this formulation is 4-6 times more efficient than usual Wilson fermions for inverting the Dirac matrix in quenched backgrounds of a 16^3 x 32 lattice at beta=6. Further results for 20^3 x 40 lattices will be reported which reveal that the...Go to contribution page
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Mr Francesco Negro (INFN - Sezione di Pisa)25/06/2014, 10:00We determine the static quark anti-quark potential for QCD at the physical point in the presence of an external magnetic field. The potential is anisotropic, in particular it is steeper in the directions orthogonal to the magnetic field than in the parallel one. The string tension increases (decreases) in the orthogonal (parallel) directions; the absolute value of the Coulomb...Go to contribution page
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Dr Krzysztof Cichy (DESY Zeuthen)25/06/2014, 10:00We present a comparison of different definitions of the topological charge on the lattice, with 2 and 2+1+1 flavours of dynamical twisted mass fermions. We give detailed results at one lattice spacing and also show that the correlation between different definitions increases as one approaches the continuum limit. The investigated definitions are: index of the overlap Dirac operator, spectral...Go to contribution page
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Prof. Colin Morningstar (Carnegie Mellon University)25/06/2014, 10:00The spectrum of excited isovector mesons is studied using a 32^3 x 256 anisotropic lattice with u,d quark masses set to give a pion mass near 240 MeV. Results in the bosonic isovector nonstrange symmetry channels of zero total momentum are presented using correlation matrices of unprecedented size. In addition to spatially-extended single meson operators, large numbers of two-meson operators...Go to contribution page
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Prof. Luigi Del Debbio (University of Edinburgh)25/06/2014, 10:00The four-fermi interaction can play an important role in models of strong dynamical EW symmetry breaking if the anomalous dimension of the four-fermi operators becomes large in the IR. The anomalous dimension can be computed nonperturbatively using a Schroedinger functional formalism. We present a computation of the four-fermi anomalous dimension for the SU(2) gauge theory with two...Go to contribution page
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Aida El-Khadra (University of Illinois)25/06/2014, 10:00We present the status of our calculation of the hadronic matrix elements for neutral B-meson mixing with asqtad sea and valence light quarks and using the Wilson clover action with the Fermilab interpretation for the b quark. We calculate the matrix elements of all five local operators that contribute to neutral B-meson mixing both in and beyond the SM. Our analysis includes MILC asqtad...Go to contribution page
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Prof. Sinya Aoki (Kyoto University)25/06/2014, 10:00We investigate some aspects of 2-flavor QCD with $m_u¥not= m_d$ at low-energy, using the leading order chiral perturbation theory including anomaly effects. While nothing special happens at $m_u=0$ for the fixed $m_d¥not=0$, the neutral pion mass becomes zero at two critical values of $m_u$, between which the neutral pion field condenses, leading to a spontaneously CP broken phase, the...Go to contribution page
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Dr Matteo Giordano (Institute for Nuclear Research (ATOMKI), Debrecen)25/06/2014, 10:00Above the QCD chiral crossover temperature, the low-lying eigenmodes of the Dirac operator are localised, while moving up in the spectrum states become extended. This localisation/delocalisation transition has been shown to be a genuine second-order phase transition, in the same universality class as that of the 3D Anderson model. The existence of localised modes and the effective dimensional...Go to contribution page
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David Richards (Jefferson Laboratory)25/06/2014, 10:20We present an investigation of the excited meson spectrum at the N_f= 3 point obtained on isotropic clover lattices with a plaquette Wilson gauge action, and a NP-improved clover fermion action, at a lattice spacing of a \simeq 0.08 fm, and compare with corresponding calculations on an anisotropic lattice at fine temporal lattice spacing but a spatial lattice spacing of a_s \simeq 0.125 fm. ...Go to contribution page
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Dr Joyce Myers (Niels Bohr Institute)25/06/2014, 10:20We develop a diagrammatic approach for calculating the chiral condensate on the lattice at strong coupling for QCD and related theories with fermions in the symmetric, antisymmetric, and adjoint representations. The approach is inspired by recent work of Tomboulis and earlier work in which the chiral condensate is obtained diagrammatically in the limit of infinite coupling. We calculate the...Go to contribution page
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Dr Tung-Han Hsieh (Academia Sinica)25/06/2014, 10:20We study the chiral properties of the pseudoscalar meson in 2-flavors lattice QCD with optimal domain-wall fermion. The gauge ensembles are generated on the $ 24^3 \times 48 $ lattice with the extent in the fifth dimension $ N_s = 16 $, and the plaquette gauge action at $ \beta = 6.10 $, for three sea-quark masses corresponding to the pion masses in the range 265-465 MeV. We calculate the mass...Go to contribution page
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Dr Ferenc Pittler (Eotvos Lorand University)25/06/2014, 10:20At low temperature the low-lying QCD Dirac spectrum obeys random matrix statistics. Recently we found that above $T_{c}$ the lowest part of the spectrum consists of localized modes that obey Poisson statistics. An interesting implication of this is that as the system crosses $T_{c}$ from above, the spectral statistics at $\lambda=0$ changes from Poisson to random matrix. Here we study this...Go to contribution page
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Mr Christian Zielinski (Nanyang Technological University, Division of Mathematical Sciences)25/06/2014, 10:20Results for the spectrum of the staggered Wilson Dirac operator in quenched backgrounds (beta = 5.8 and 6) are presented for a range of different lattice sizes up to 16^3 x 32. Significant improvement in the physical branch of the spectrum is observed for the larger lattices. The results are also compared with spectrum results for the usual Wilson Dirac operator in the same backgrounds.Go to contribution page
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Dr Yoshiaki Koma (Numazu College of Technology)25/06/2014, 10:20We study the static three-quark potential in SU(3) lattice gauge theory at zero temperature with the Polyakov loop correlation function (PLCF) consisting of three Polyakov loops. Compared to the use of the three-quark Wilson loop, the PLCF allows us to investigate the ground state potential of various three-quark configurations in detail with less systematic effects. We overcome the problem...Go to contribution page
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Mr Justus Tobias Tsang (University of Southampton)25/06/2014, 11:10We study the feasibility of using a novel discretisation (Moebius) to directly simulate charm physics within the Domain Wall formalism. We then present results for a range of physical quantities including meson masses as well as decay constants and the dispersion relation of heavy-heavy (eta_c) and heavy-strange (D_s) pseudoscalar mesons. Four extensive sets of tree-level Symanzik pure gauge...Go to contribution page
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Mr Atsuro Ikeda (Osaka University)25/06/2014, 11:10We study the charmonium property at finite temperature and finite momentum in quenched lattice QCD with improved maximum entropy method (MEM). We extend the MEM analysis to the product space of the correlation functions at more than two different momenta to take advantage of more data and the strong correlation among Euclidean correlators with different momenta. We find that this method...Go to contribution page
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Mr Masayuki Wakayama (Nagoya University)25/06/2014, 11:10Our purpose is to obtain insights of structure of the sigma meson from lattice QCD. At present we do not reach a conclusive understanding of nature of the sigma meson. Currently it is considered as a usual two-quark state, four-quark states such as a tetra-quark and mesonic molecules or superposition of them. At present we do not reach a conclusive understanding of nature of the sigma meson....Go to contribution page
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Dr Richard Brower (Boston University)25/06/2014, 11:10Lattice radial quantization is a nonperturbative method especially suited to numerically solve Euclidean conformal field theories. Tests are made for the critical surface of the phi 4th theory at the Wilson-Fisher critical point in 3D on R x S2 and in 2D on the Riemann sphere. Simplicial lattice using the Finite Element Methods (FEM) or Regge calculus discretization are need to...Go to contribution page
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Mr Stefano Piemonte (WWU Münster)25/06/2014, 11:10The behaviour of supersymmetric theories at finite temperatures differs from that of other theories in certain aspects. Due to the different thermal statistics of bosons and fermions, supersymmetry is explicitly broken for any non-zero value of the temperature. We study the N=1 supersymmetric Yang-Mills theory on the lattice at finite temperatures. This model is the simplest supersymmetric...Go to contribution page
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Dr Georg von Hippel (University of Mainz)25/06/2014, 11:10TalkWe study the ability of a variety of fitting techniques to extract the ground state matrix elements of the vector current from ratios of nucleon three- and two-point functions that contain contaminations from excited states. Extending our high-statistics study of nucleon form factors, we are able to demonstrate that the treatment of excited state contributions in conjunction with approaching...Go to contribution page
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Marco Cè (Scuola Normale Superiore, Pisa, Italy and INFN, Sezione di Pisa, Italy)25/06/2014, 11:10We present a precise computation of the topological charge distribution in the SU(3) Yang–Mills theory. It is carried out on the lattice with high statistics Monte Carlo simulations by employing the clover discretization of the field strength tensor combined with the Yang–Mills gradient flow. The flow equations are integrated numerically by a fourth-order structure-preserving Runge–Kutta...Go to contribution page
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Yannick Meurice (University of Iowa)25/06/2014, 11:30The idea of blocking in configuration space has played an important role in the development of the RG ideas. However, despite being half a century old and having had a huge intellectual impact, generic numerical methods to perform blocking for lattice models have progressed more slowly than sampling methods. Blocking may be essential to deal with near conformal situations. Typically,...Go to contribution page
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Dr Andreas Juettner (University of Southampton)25/06/2014, 11:30This talk will provide an overview of RBC/UKQCD's charm project on their 2+1 flavour physical point ensembles using Moebius Domain Wall Fermions for the light as well as for the charm quark. After a brief motivation of DWF as a suitable heavy quark discretisation we will show first results for masses and matrix elements.Go to contribution page
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Joshua Berlin (University of Frankfurt)25/06/2014, 11:30The structure of the light-scalar meson a_0(980) is under debate. It might be of quark-antiquark, diquark-antidiquark or mesonic molecule type. We have implemented corresponding interpolating field operators composed of two and of four quarks, as well as operators of two-meson type, to study the structure of a_0(980). The computation of the correlation matrix is rather challenging, because of...Go to contribution page
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Dr ANOSH JOSEPH (Deutsches Elektronen-Synchrotron DESY)25/06/2014, 11:30Certain classes of supersymmetric gauge theories, including the well known N=4 super Yang-Mills (SYM) theory, that takes part in the AdS/CFT correspondence, can be formulated on a Euclidean spacetime lattice using the techniques of exact lattice supersymmetry. Great ideas such as topological twisting, Dirac-Kahler fermions, geometric discretization all come together to create gauge theories...Go to contribution page
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Mr Florian Meyer (University of Bielefeld, Germany)25/06/2014, 11:30We present new results on the reconstruction of mesonic spectral functions for three temperatures above T_c in quenched QCD. Making use of Clover improved Wilson valence quarks allows for a clean extrapolation of correlator data to the continuum. For the case of vanishing momentum the spectral function is obtained by fitting the data to a well motivated ansatz. In the vector channel for...Go to contribution page
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Dr Giannis Koutsou (The Cyprus Institute)25/06/2014, 11:30TalkThe electromagnetic form factors of the nucleon using twisted mass fermion configurations simulated by the ETM collaboration are presented. These include a gauge field ensemble simulated with two degenerate light quarks yielding a pion mass of around 130 MeV, as well as two ensembles yielding pion masses of 210 MeV and 370 MeV with additional strange and charm sea quarks tuned to their...Go to contribution page
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Dr Andre Sternbeck (University of Regensburg)25/06/2014, 11:30We investigate the exact gluonic Dyson-Schwinger equation of quenched SU(n) lattice gauge theory in Landau gauge and the lattice analog of the Kugo-Ojima confinement criterion.Go to contribution page
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Dr Abdou Abdel-Rehim (The Cyprus Institute)25/06/2014, 11:50We carry out a study of the light scalar meson a_0(980) employing interpolating field operators of quark-antiquark, diquark-antidiquark, mesonic molecules and two-particle meson operators. Both connected and disconnected quark loops are investigated. We present preliminary results for two ensembles of 2+1 clover fermion gauge configurations generated by the PACS-CS collaboration...Go to contribution page
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Urs Wenger (University of Bern)25/06/2014, 11:50The conjectured holographic duality between supersymmetric Yang-Mills quantum mechanics and type IIa string theory in principle allows to probe the physics of certain supergravity black holes by lattice Monte Carlo simulations. In this talk we derive the fermion loop formulation of the 4 and 16 supercharge SU(N) theory on the lattice. The loop formulation naturally separates the...Go to contribution page
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Mr Yong-Gwi Cho (University of tsukuba)25/06/2014, 11:50We present scaling studies for heavy-quark observables calculated with an O(a^2)-improved fermion action on tree-level Symanzik improved gauge configurations. Lattices of 1/a = 2.0-3.7 GeV with an equal physical volume ~1.6 fm are used. The results are compared with the standard domain-wall and naive Wilson fermions.Go to contribution page
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Dr Shigemi Ohta (Institute of Particle and Nuclear Physics, KEK)25/06/2014, 11:50TalkAnalyses on possible systematics in some isovector nucleon observables in the RBC+UKQCD 2+1-flavor dynamical domain-wall fermion (DWF) lattice-QCD will be presented. The reports will be based mostly on the RBC+UKQCD Iwasaki+DSDR ensemble at pion mass of 170 MeV. The vector charge, axial charge, quark momentum and helicity fractions, and transversity are discussed. No autocorrelation issue...Go to contribution page
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Mr Tim Harris (Trinity College, University of Dublin)25/06/2014, 11:50I will present updated results from the FASTSUM collaboration on the bottomonium spectrum at finite temperature from lattice NRQCD on anisotropic $N_f=2+1$ Wilson clover ensembles. Further systematic checks on the reconstruction of the spectral function at high temperatures where few correlator data are available will be discussed. This is relevant to understand the reliability of the...Go to contribution page
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Dr Urs Gerber (Instituto de Ciencias Nucleares - Universidad Nacional Autonoma de Mexico)25/06/2014, 11:50We consider models with topological sectors and difficulties with their Monte Carlo simulation. In particular, we are concerned with the situation where a simulation has a very long auto-correlation time with respect to the topological charge. In such cases, reliable numerical measurements are only possible within single topological sectors. The challenge is to assemble such restricted...Go to contribution page
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Dr Paulo Silva (University of Coimbra)25/06/2014, 11:50The Z(N) dependence of the pure Yang-Mills gluon propagator, in the Landau gauge, is investigated at finite temperature for N=3. Special attention will be given to the behaviour near the critical temperature Tc. Our simulations show a complex pattern as expected in a first order phase transition. Furthermore, we identify an order parameter directly associated with the breaking of the SU(3)...Go to contribution page
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Mr Javad Komijani (Washington University in St. Louis)25/06/2014, 12:10We present final results for decay constants of charmed and strange pseudoscalar mesons, calculated on MILC ensembles with four dynamical quarks. The HISQ action is used for both the valence and sea quarks. A straightforward analysis on the ensembles with physical quark masses, which avoids the need for chiral perturbation theory, is performed first. We report the resulting values for...Go to contribution page
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Mr Attila Pasztor (MTA-ELTE Lendulet Lattice gauge theory research group/Eotvos University)25/06/2014, 12:10Finite temperature charmonium spectral functions in the pseudoscalar and vector channels are studied in lattice QCD with 2+1 flavours of dynamical Wilson quarks, on fine isotropic lattices (with a lattice spacing of 0.057fm), with a pion mass of 545MeV. The highest temperature studied is approximately 1.4Tc. Up to this temperature no significant variation of the spectral function is seen in...Go to contribution page
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Dr Andrea Guerrieri (Dipartimento di fisica e INFN Roma "Tor Vergata")25/06/2014, 12:10The very recent confirmation of the Z(4430) charged resonance by the LHCb experiment strongly suggests the existence of QCD bound states with four quarks. We report some preliminary results about hypothetical flavored tetraquark hadrons. Such states are particularly amenable to Lattice QCD studies as their interpolating operators do not overlap with those of ordinary hidden-charm mesons.Go to contribution page
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Arthur Dromard (Goethe Universität, Frankfurt am Main)25/06/2014, 12:10Lattice QCD simulations tend to become stuck in a single topological sector at fine lattice spacing or when using chirally symmetric overlap quarks. In such cases physical observables differ from their full QCD counterparts by finite volume corrections, which need to be understood on a quantitative level. We discuss extensions of existing relations from the literature between correlation...Go to contribution page
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Dr Parikshit Junnarkar (Helmholtz Institut Mainz)25/06/2014, 12:10We present preliminary results on the axial form factor G_A(Q^2) and the induced pseudo-scalar form factor G_P(Q^2) of the nucleon. The relevant matrix elements were computed on CLS ensembles with N_f =2 non-perturbatively improved O(a) Wilson fermions at three lattice spacings, namely a = 0.050, 0.063, 0.079 fm. These calculations were performed with pion masses ranging from as low as m_pi =...Go to contribution page
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Prof. Simon Catterall (Syracuse University)25/06/2014, 12:10N=4 Yang-Mills may be formulated on the lattice in such a way as to preserve one exact supersymmetry. This has remarkable consequences; the beta function of the lattice theory vanishes at one loop, the moduli space of the theory survives to all orders of perturbation theory and a maximum of two fine tunings are required to take the continuum limit. I will review the formulation and...Go to contribution page
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Mr Roman Hoellwieser (NMSU)25/06/2014, 12:10We present a method to smear (center projected) Z(2) vortices in order to obtain properties of the original (full) SU(2) configurations. In particular we address the problem that Z(2) configurations cannot be treated with overlap (or chirally improved) fermions due to their lack of smoothness. We develop a method to regain this smoothness and simultaneously maintain the center vortex...Go to contribution page
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Prof. Constantia Alexandrou (University of Cyprus)25/06/2014, 12:30TalkWe present results on the axial charges of the nucleon, the hyperons and charmed baryons using a number of twisted mass fermions ensembles. This includes an $N_f=2$ ensemble with the physical value of the pion mass for which we also show results on the tensor structure of the nucleon.Go to contribution page
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Mr Daniel Trewartha (University of Adelaide)25/06/2014, 12:30The fundamental aspects of the QCD vacuum that are responsible for the dynamical generation of mass through chiral symmetry breaking is an ongoing source of debate. We investigate the role of centre vortices in dynamical mass generation using overlap fermions. The exact chiral symmetry that the overlap fermion action possesses yields a distinctive response to the underlying topology of the...Go to contribution page
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Prof. Ethan Neil (University of Colorado, Boulder)25/06/2014, 12:30We present the status of our updated D and B meson decay-constant analysis, based on the MILC Nf=2+1 asqtad gauge ensembles. Heavy quarks are incorporated using the Wilson clover action with the Fermilab interpretation. This analysis includes ensembles at five lattice spacings from a=0.045 to 0.15 fm, and light-quark sea masses down to 1/20 of the strange-quark mass. A complete...Go to contribution page
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Dr Michele Pepe (INFN)25/06/2014, 12:30We report on an ongoing project of determining non-perturbatively the finite renormalization constants of the energy-momentum tensor in the SU(3) Yang-Mills theory. We compute them by imposing on the lattice suitable Ward Identites at finite temperature and volume in presence of shifted boundary conditions. We present accurate preliminary numerical data for values of the bare coupling g_0^2...Go to contribution page
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Dr Hiroshi Ohno (Center for Computational Sciences, University of Tsukuba)25/06/2014, 12:30Quarkonium properties at finite temperature are studied with various quark masses in the range between those for the charm and bottom quarks. Our simulations are performed in quenched QCD with the $O(a)$-improved Wilson quarks on large and fine isotropic lattices at temperatures between about 0.7$T_c$ and 1.4$T_c$. At both vanishing and finite momenta we discuss temperature and quark mass...Go to contribution page
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Dr Jeremy Green (Institut für Kernphysik, Johannes Gutenberg-Universität Mainz)25/06/2014, 12:30Early results will be presented from a Lattice QCD study seeking a bound H-dibaryon using Nf=2 flavors of O(a) improved Wilson fermions and a quenched strange quark. We solve the generalized eigenvalue problem constructed using a variational basis of interpolators consisting of the two independent local products of six positive-parity-projected quarks with the appropriate quantum numbers,...Go to contribution page
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Joel Giedt (Rensselaer Polytechnic Institute)25/06/2014, 12:30We know from previous studies that the symetries of the twisted Q-symmetric lattice theory are particularly powerful in terms of protecting the long distance effective theory from unwanted renormalizations. Here, it will be shown that rescalings of the lattice fields imply that only two fine-tunings are required, so that the N=4 theory is on a similar footing to clover fermions in...Go to contribution page
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Chia Cheng Chang (University of Illinois)25/06/2014, 12:50We present the status of our calculation of the D-meson mixing hadronic matrix elements for all five short-distance operators. We use the $N_{f}=2+1$ asqtad gauge field ensembles generated by the MILC collaboration involving four lattice spacings ranging from 0.12 to 0.045 fm and up/down to strange quark mass ratios as low as 0.05. For the charm quark we use the Sheikholeslami-Wohlert action...Go to contribution page
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Dr Rajan Gupta (Los Alamos National Lab)25/06/2014, 12:50This talk will present an update on the calculation of iso-vector nucleon charges g_A, g_S and g_T by the PNDME collaboration. The calculations are being done using clover valence quarks on 2+1+1 flavor HISQ lattices generated by the MILC collaboration at multiple values of the lattice spacing, light quark masses and lattice volumes. To extrapolate in the lattice volume, lattice spacing and...Go to contribution page
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David Schaich (Syracuse University)25/06/2014, 12:50I will present results from numerical lattice studies of maximally (N=4) supersymmetric Yang--Mills theory with gauge group SU(2), based on a lattice formulation that exactly preserves one supersymmetry. While the pfaffian of the lattice theory is not manifestly real, direct measurements of the pfaffian show it to be approximately real and positive on all accessible lattice volumes. Studies...Go to contribution page
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Dr Alexander Rothkopf (Institute for Theoretical Physics, Heidelberg University)25/06/2014, 12:50We present the latest results from two projects focused on determining the temperature dependence of the heavy quark potential from lattice QCD. The real and imaginary part of this real-time potential is obtained from the position and width of the lowest lying peak in the Coulomb gauge Wilson line correlator spectral function [1]. Spectral information is extracted from Euclidean time data...Go to contribution page
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Hidenori Fukaya (Osaka University)25/06/2014, 12:50Global topological charge tends to decorrelate very slowly or to even freeze on fine lattice simulations, while local topological fluctuations are expected to survive and lead to correct physical results as long as the volume is large enough. We investigate this issue on the recently generated configurations including dynamical domain-wall fermions at a=0.08 fm and finer. We utilize the...Go to contribution page
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Dr Zohreh Davoudi (Institute for Nuclear Theory-University of Washington)25/06/2014, 12:50We explore the use of twisted boundary conditions in extracting the nucleon mass and the binding energy of two-baryon systems, such as the deuteron, from Lattice QCD calculations. Using the experimentally determined phase shifts and mixing angles, and utilizing the Luescher method extended to baryonic systems with twisted boundary conditions, we determine the expected energies of the deuteron...Go to contribution page
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Dr Anthony Mezzacappa (Oak Ridge National Laboratory)26/06/2014, 09:00Talk
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Yasumichi Aoki (Nagoya University)26/06/2014, 09:45Talk
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Dr Brendan Casey (Fermilab)26/06/2014, 11:00Talk
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Dr Antonin Portelli (University of Southampton)26/06/2014, 11:30Talk
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Dr Francesco Sanfilippo (University of Southampton)26/06/2014, 12:00Talk
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Mr Ciaran Hughes (DAMTP, University of Cambridge)26/06/2014, 14:15Recently Lewis and Woloshyn's exploratory study using lattice NRQCD to study the radiative decay $\Upsilon(2S) \to \eta_b(1S) \gamma$ found that next-to-leading order ($v^6$) contributions were large compared to the leading order ($v^4) result. We explain this suppression of the $v^4$ term using a simple potential model. We then present our lattice QCD results obtained with three lattice...Go to contribution page
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Dr Benjamin Svetitsky (Tel Aviv University)26/06/2014, 14:15We have carried out a Schrodinger-functional calculation for the Abelian gauge theory with Nf=2 four-component fermions in three dimensions. We find no fixed point in the beta function, meaning that the theory is confining rather than conformal.Go to contribution page
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Mr Michael Lujan (The George Washington University)26/06/2014, 14:15TalkKnowledge of the electric polarizability is crucial to understand the interactions of hadrons with electromagnetic fields. The neutron polarizability is very sensitive to the quark mass and is expected to diverge in the chiral limit. Here we present results for the electric polarizability of the neutron, neutral pion, and neutral kaon on eight ensembles with nHYP-smeared clover dynamical...Go to contribution page
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Prof. Apoorva Patel (Indian Institute of Science, Bangalore, India)26/06/2014, 14:15A specific unitary evolution operator can be constructed in many different ways, corresponding to different Hamiltonian trajectories between the desired end-points. An optimal trajectory can then be selected to make the evolution have the best computational complexity and control over errors. Using Grover's quantum search algorithm as an explicit example, it is shown that the complexity...Go to contribution page
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Prof. Leonid Glozman Glozman (University of Graz)26/06/2014, 14:15Using the overlap Dirac operator we remove its lowest-lying eigenmodes from the valence quark propagators and study evolution of the J=1 meson masses. At the truncation energy about 50 MeV we observe a degeneracy of all possible U(2)_L * U(2)_R multiplets, i.e. the observed quantum levels have a symmetry larger than U(2)_L * U(2)_R and their energy does not depend on the spin...Go to contribution page
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Takashi Umeda (Hiroshima University)26/06/2014, 14:15The fixed scale approach has various advantages to calculate the QCD equation of state on lattices. In this approach a series of temperatures are realized with single coupling parameters. Therefore zero temperature subtractions are common, and conditions for the line of constant physics are automatically satisfied. We test the fixed scale approach to study thermodynamics of SU(3) gauge theory...Go to contribution page
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Dr Patrick Fritzsch (Humboldt University Berlin)26/06/2014, 14:15We review our new strategy and current status towards a high precision computation of the Lambda parameter from three-flavour simulations in QCD. To reach this goal we combine specific advantages of the Schroedinger functional and gradient flow couplings.Go to contribution page
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Dr Holger Perlt (Leipzig university)26/06/2014, 14:35Renormalization factors are needed to related lattice quantities to their corresponding continuum counterparts. In order to renormalize singlet observables one has to include connected and disconnected diagrams. Especially, the disconnected contributions are very difficult to calculate using the standard three-point function technique. The Feynman-Hellmann method provides the possibility to...Go to contribution page
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Mr Daniel Körner (FSU Jena)26/06/2014, 14:35We study the non-perturbative renormalization group flow of the nonlinear O(N) sigma model in two and three space-time dimensions using a scheme that combines an effective local Hybrid Monte Carlo update routine, blockspin transformations and a Monte Carlo demon method. In two dimensions our results verify perturbative renormalizability. In three dimensions, we determine the flow...Go to contribution page
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Mr Ryo IWAMI (Niigata University)26/06/2014, 14:35We discuss the reweighting method aiming numerical studies of QCD at finite density, in which the Monte-Carlo method cannot be applied directly. One of the most important problems in the reweighting method is the overlap problem. To solve the problem, we propose the following reweighting method: simulations are performed at several simulation points and the analysis is done combining all data....Go to contribution page
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Dr Walter Freeman (George Washington University)26/06/2014, 14:35TalkThe contribution of the sea quark charges is a large uncertainty in lattice calculations of hadron polarizabilities; we present an update in our use of perturbative reweighting in the quark charge to address this issue. The difficult aspect of this calculation is the stochastic estimation of the weight factor expansion coefficients. We use aggressive (large-N) dilution, consisting of...Go to contribution page
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Mr Victor Braguta (IHEP)26/06/2014, 14:35The axial magnetic field, which couples to left- and right-handed fermions with opposite signs, may generate an equilibrium dissipationless energy flow of fermions in the direction of the field even in the presence of interactions. In this report numerical observation of the Axial Magnetic Effect in SU(2) lattice gauge theory is presented. The temperature behavior of the Axial Magnetic Effect...Go to contribution page
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Judah Unmuth-Yockey (University of Iowa)26/06/2014, 14:35We study the two-dimensional O(3) model on the lattice using the Tensor Renormalization Group (TRG) approach, with the goal of understanding asymptotic scaling at both the large volume, and large beta limit. Harmonic analysis on the Boltzmann weight introduces a sign problem into the partition function, which makes the model difficult to study with the Worm Algorithm. The TRG...Go to contribution page
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Dr JONG-WAN LEE (City College of New York)26/06/2014, 14:55TalkWe discuss the resolution of inconsistencies between the background field method in lattice QCD and the effective field theory matching conditions. Lack of on-shell conditions in lattice QCD with time-dependent background fields requires that operators related by equations of motion in the effective field theory should be retained in the action to describe the Green's function correctly. As a...Go to contribution page
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Felix Stollenwerk (Humboldt University Berlin)26/06/2014, 14:55We develop a strategy for the non-perturbative determination of the O(\(a\))-improvement coefficient \(c_{\rm sw}\) for Wilson fermions with massive sea quarks. The improvement condition is defined via the PCAC relation in the Schrödinger functional. It is imposed along a line of constant physics designed to be close to the correct mass of the charm quark. The numerical work uses the...Go to contribution page
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Dr Roger Horsley (University of Edinburgh)26/06/2014, 14:55SU2 isospin breaking effects in hadron octet and decuplets are due to a combination of up and down quark mass differences and electromagnetic effects. Usually these masses difference are small. Between the Sigma and Lambda the splitting is much larger due to mixing between these states. We determine the QCD mixing matrix and hence find the mixing angle and mass splitting. Provided the...Go to contribution page
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Dr Agostino Patella (CERN and Plymouth University)26/06/2014, 14:55The energy-momentum tensor in lattice gauge theories requires renormalization because of the breaking of Poincare' group. The Wilson flow can be used in principle to set up non-perturbative, well-defined and, possibly, practically convenient strategies to define a properly renormalized energy momentum tensor. I will present some preliminary data in this direction.Go to contribution page
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Dr Maksim Ulybyshev (Regensburg University)26/06/2014, 14:55Tight-binding model of Graphene with vacancies in crystal structure was studied within the framework of Hybrid Monte Carlo simulations. Antiferromagnetic ordering is observed in the vicinity of the vacant sites. Mass gap is extracted from the calculations of the two-point Euclidean Green function. It is demonstrated that even a relatively small concentration of vacancies can lead to opening a...Go to contribution page
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Mr Norbert Trombitas (Eotvos Lorand University)26/06/2014, 14:55We study 2+1 flavour QCD thermodynamics using Wilson fermions in the fixed scale approach. The temperature dependence of the renormalized chiral condensate, quark number susceptibility and Polyakov loop is determined at three pion masses down to 280~MeV. Four lattice spacings are used allowing for a controlled continuum limit.Go to contribution page
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Dr Alexander Molochkov (Far Eastern Federal University)26/06/2014, 14:55The most important probes for the phase states of a four-dimensional gauge field theory are the Wilson and t'Hooft line operatros that are defined on one-dimensional curves in the space-time. However, for more detail understanding of four-dimensional gauge field theory dynamics and vacuum topology we need additional probes expressed by operators defined on the subspaces with higher dimensions....Go to contribution page
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Mr Mark Wurtz (York University)26/06/2014, 15:15Gauge-invariant sources with a hydrogen wave function shape are constructed for bottomonium two-point correlation functions using the free-form smearing technique. The bottomonium spectrum is extracted from free-form smeared correlation functions. Results are compared with conventional smearing techniques.Go to contribution page
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Mr Alexander Nikolaev (Far Eastern Federal University)26/06/2014, 15:15Tight-binding model of the AA-stacked bilayer graphene with screened electron-electron interactions has been studied using the Hybrid Monte Carlo simulations on the original double-layer hexagonal lattice. Instantaneous screened Coulomb potential is taken into account using Hubbard-Stratonovich transformation. G-type antiferromagnetic ordering has been studied and the phase transition with...Go to contribution page
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Dr Stefan Krieg (Forschungszentrum Juelich GmbH/Wuppertal University)26/06/2014, 15:15I will review results for the Equation of State of QCD, in particular I will give an update on our calculation that includes a dynamical charm quark.Go to contribution page
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Prof. Jacek Wosiek (Jagellonian University)26/06/2014, 15:15Screening of external charges by electric fluxes induced by periodic boundary conditions in two dimensional gauge theories will be discussed. Subsequently, the less known problem of introducing sources with arbitrary charge, i.e. non-congruent with an elementary one, will be presented and elaborated. Finally the new, classical continuum limit of lattice formulation will be proposed and...Go to contribution page
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Prof. Masanori Okawa (Hiroshima University)26/06/2014, 15:15Last year, we proposed a new method to extract string tension using 4-dimensional smearing method (PL B718 (2013) 1524). In this talk we first show that results using smearing method are equivalent to those obtained by Wilson flow once the time step \epsilon is sufficiently small. We then demonstrate the practical advantage of our method by applying it to the calculation of Creutz ratio in...Go to contribution page
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Maarten Golterman (San Francisco State University)26/06/2014, 15:15When a subgroup of the flavor symmetry group of a gauge theory is weakly coupled to additional gauge fields, the vacuum tends to align such that the gauged subgroup is unbroken. At the same time, the lattice discretization typically breaks the flavor symmetry explicitly, and can give rise to new lattice-artifact phases with spontaneously broken symmetries. We discuss the interplay of...Go to contribution page
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Kadir Utku Can (Tokyo Institute of Technology)26/06/2014, 15:35The electromagnetic form factors of \Sigma_c, \Xi_cc, \Omega_c and \Omega_cc baryons are computed and their electric and magnetic charge radii as well as their magnetic moments are extracted in 2+1 flavor Lattice QCD. Extrapolated physical point results show that the charge radii and magnetic moments are smaller compared to those of, e.g., proton. Investigating the individual quark...Go to contribution page
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Dr Dominik Smith (TU Darmstadt)26/06/2014, 15:35We report on the status of our ongoing Hybrid-Monte-Carlo simulations of the tight-binding model for the electronic properties of graphene, using a realistic potential for the two-body interactions. Our short-range interactions thereby include the partial screening due to electrons in higher energy states from ab initio calculations based on the constrained random phase approximation...Go to contribution page
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Mr Masanori for HAL QCD Coll Yamada (University of Tsukuba)26/06/2014, 15:35We report our results of central potential between two Omega baryons from 2+1 flavor full Lattice QCD simulation.In the past studies, there is a possibility that some decuplet baryons have a bound state. However, almost all decuplet baryons are unstable due to decays via the strong interaction. An exception is the Omega decuplte baryon, which is stable against the strong decays, so its...Go to contribution page
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Tanmoy Bhattacharya (LANL)26/06/2014, 15:35The HotQCD Collaboration has calculated the equation of state in 2+1 flavor QCD at zero net baryon density using the Highly Improved Staggered Quark (HISQ) action. The strange quark mass was set to its physical value and the light (up/down) quark masses used correspond to a pion mass of 160 MeV in the continuum limit. Lattices with temporal extent Nt=6, 8, 10 and 12 were used, and the...Go to contribution page
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Dr Daniel Nogradi (Eotvos University)26/06/2014, 15:35The Yang-Mills gradient flow is considered in lattice perturbation theory at leading order of the gauge coupling and O(a^8) in the lattice spacing. Improved actions are incorporated for the gauge action, the flow itself and the observable for E(t). The results lead to a setup with O(a^6) improvement at tree level.Go to contribution page
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Mr Shinya Gongyo (Kyoto University)26/06/2014, 15:35We study numerically the phase structure in two dimensions with SU(2) gauge-Higgs coupling. We calculate the static potential from Wilson Loop, W propagator and the order parameter related to a transition between the confinement-like phase and Higgs-like phase. Our results suggest that there is a confinement-like phase and Higgs-like phase, even in two dimensions. In the confinement-like...Go to contribution page
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Stefan Sint (Trinity College Dublin & NIC@DESY-Zeuthen)26/06/2014, 15:55The gradient flow has become a very useful tool both for scale setting and for defining suitable finite volume schemes for the gauge coupling. However, surprisingly large cutoff effects have been observed in some cases. We here investigate these effects at leading order in perturbation theory and reproduce qualitative features that have previously been observed in the context of scale setting....Go to contribution page
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Dr Oleg Pavlovskiy (Moscow State University)26/06/2014, 15:55New formulation of path integrals for relativistic quantum systems will discussed. Influence of the relativistic effects on the properties of quantum systems will be studied by means of the Monte Carlo method. A generalization of this approach to the case the path integral quantization of the Born-Infeld field theory will also discussed.Go to contribution page
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Dr Takumi Doi (RIKEN)26/06/2014, 15:55Recently, the determination of three-nucleon forces attracts a great deal of interest in light of their role in nuclear and astrophysical phenomena such as EoS of nuclear matter and the structure of the neutron star core. In this talk, we present the lattice QCD calculation of three-nucleon forces utilizing the time-dependent HAL QCD method. In particular, we study the quark mass dependence...Go to contribution page
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Mr Christian Shultz (Old Dominion University)26/06/2014, 15:55TalkWe present a progress update on an ongoing calculation aimed at extracting photocouplings in the light-quark sector from radiative matrix elements computed using lattice QCD. These couplings drive the rate of photo production of mesons, of particular interest are exotic and hybrid mesons which while present in lattice calculations have yet to be observed experimentally. The use of distillation...Go to contribution page
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Dr Prasad Hegde (Central China Normal University)26/06/2014, 15:55Hydrodynamic models of heavy-ion collisions have increasingly begun to rely on lattice results for the Equation of State. While the lattice has the advantage of being a first-principles approach to QCD, the notorious sign problem prevents a direct determination of the equation of state and other thermodynamic observables at finite chemical potential $\mu_B$. Quark number susceptibilities...Go to contribution page
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Mithat Unsal (North Carolina State University)26/06/2014, 15:55This talk presents a summary of our current understanding of confinement problem in non-abelian gauge theories. It is dedicated to the memory of Pierre van Baal, who contributed to the field significantly. I will review recent semi-classically calculable realization of confinement in various gauge theories. In particular, I will describe the role of monopole-instantons(realized by van...Go to contribution page
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Prof. Sinead Ryan (Trinity College Dublin)26/06/2014, 16:15Preliminary results from a study of $DK$ and $D\pi$ scattering are presented using a set of anisotropic $N_f=2+1$ dynamical gauge field configurations generated by the Hadron Spectrum Collaboration. The variational method with a large operator basis is used in two lattice volumes to determine the excitation spectra of open charm mesons with the relevant scattering states containing one...Go to contribution page
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Mr Benjamin Owen (University of Adelaide)26/06/2014, 16:15TalkOver the past decade there has been significant experimental interest into the electromagnetic excitation of nucleon resonances and their underlying structure. Given the large body of data that now exists, it is interesting to consider the expectations presented by QCD. Correlation matrix techniques present us with the ideal approach to extracting matrix elements of hadronic excitations....Go to contribution page
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Dr Christopher Monahan (College of William and Mary)26/06/2014, 16:15We propose a new ``smeared'' operator product expansion (sOPE) in which the set of local operators in the OPE are replaced by their locally smeared counterparts, generated by the gradient flow. The flow time, or smearing, parameter serves as a regulator for both Wilson coefficients and operator products. Matrix elements determined nonperturbatively on the lattice using smeared degrees of...Go to contribution page
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Mr Semen Valgushev (Institute for Theoretical and Experimental Physics)26/06/2014, 16:15The results of numerical simulation of graphene effective field theory in external magnetic field are presented. The numerical simulation is performed using noncompact (3+1)-dimensional Abelian lattice gauge fields and (2+1)-dimensional staggered lattice fermions. The dependences of fermion condensate and conductivity on the dielectric permittivity of the substrate for different values of...Go to contribution page
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Dr Chris Schroeder (LLNL)26/06/2014, 16:15On behalf of the HotQCD collaboration, I present results from the first lattice study of the QCD phase transition using chiral fermions and physical quark masses. With domain wall fermions, the dislocation suppressing determinant ratio (DSDR), a temporal Euclidean extent of 8 sites, and spatial extents of at least 4 and up to 11 fm, we have computed the disconnected chiral susceptibility for...Go to contribution page
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Prof. Sasa Prelovsek (University of Ljubljana)27/06/2014, 09:00Talk
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Dr Denes Sexty (Institut für Theoretische Physik, Universität Heidelberg)27/06/2014, 09:45Talk
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Dr Alberto Ramos (NIC @ DESY, Zeuthen)27/06/2014, 10:15Talk
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27/06/2014, 11:15
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Prof. Tetsuya Onogi (Osaka University)27/06/2014, 11:45TalkThe emergence of massless Dirac fermion in graphene has attracted attention in recent years due to the remarkable features. The tight-binding honeycomb lattice hamiltonian to explain this feature has a close analogy with "the staggered fermion" which is widely used in lattice gauge theory. Employing the position space formalism developed in lattice gauge theory, we reformulate the...Go to contribution page
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Ms Yuko Murakami (Hiroshima University)27/06/2014, 14:15We investigate the universality of Möbius Domain Wall Fermions (MDWF) in the Schrödinger Functional (SF) scheme at tree level. We introduce the SF boundary condition to the MDWFs by adding a temporal boundary operator. When the fifth dimensional parameters of the MDWF are a constant, this construction seems to be natural according to the Luescher’s universality prescription for the overlap...Go to contribution page
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Dr Francesco Di Renzo (University of Parma and INFN)27/06/2014, 14:15In the context of thimble regularization of lattice field theories we are developing a new simulation algorithm. The main difficulty is to devise a sampling of configurations on a non-trivial manifold, which is defined as the hypersurface formed by the union of all paths of steepest descent of the complex action ending in a given saddle point. The main point with the new algorithm is the...Go to contribution page
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Richard Lau (University of Oxford)27/06/2014, 14:15We present our current results for the deconfining temperatures in SO(N) gauge theories in 2+1 dimensions. SO(2N) theories may help us to understand QCD at finite chemical potential since there is a large-N orbifold equivalence between SO(2N) QCD-like theories and SU(N) QCD and SO(2N) theories do not have the sign problem present in QCD. We show that the deconfining temperatures in these two...Go to contribution page
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Prof. Gerrit Schierholz (DESY)27/06/2014, 14:15First results on electromagnetic mass splittings of octet mesons and baryons from a fully dynamical simulation of QCD+QED are presented.Go to contribution page
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Dr William Detmold (MIT)27/06/2014, 14:15We consider QCD-like, composite models of dark matter and investigate what role nuclear physics may play in the dark sector. We compute the multi-particle spectrum of SU(N_c=2) gauge theory with two fundamental fermions, finding strong evidence for the existence of bound multi-hadron systems (nuclei) in this theory. We briefly discuss the rich phenomenological consequences of such strong...Go to contribution page
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Ms Emilie Huffman (Duke University)27/06/2014, 14:15We present a solution to the sign problem in a class of particle-hole symmetric Hamiltonian lattice fermion models on bipartite lattices using the idea of fermion bags. The solution remains valid when the particle hole symmetry is broken through a staggered chemical potential term. This solution allows, for the first time, simulations of some massless four-fermion models with minimal...Go to contribution page
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Marina Marinkovic (University of Southampton)27/06/2014, 14:15TalkWe present steps towards the computation of the leading-order hadronic contribution to the muon anomalous magnetic moment on RBC/UKQCD physical point DWF ensembles. We discuss several methods for controlling and reducing uncertainties associated to the determination of the HVP form factor.Go to contribution page
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Mr Matthias Puhr (University Regensburg)27/06/2014, 14:35The overlap Dirac operator at finite chemical potential can be efficiently computed with the two-sided Lanczos algorithm. Compared with other methods the Lanczos algorithm has the advantage that it takes into account information about the source vector when constructing an approximation to the overlap operator. In order to study transport coefficients in terms of correlators of conserved...Go to contribution page
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Prof. Artan Borici (Uiversity of Tirana)27/06/2014, 14:35It is well known that Crank-Nicolson discretization scheme is second order accurate in time. Its application in the case of the Dirac operator leads to a lattice theory with reduced doublers and broken parity. Adding a 3-space Wilson term one obtains a single fermion which is second order accurate in time. In the case of an imaginary term the doubler degeneracy is lifted and the ground state...Go to contribution page
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Prof. Claude Bernard (Washington University St. Louis)27/06/2014, 14:35We report on the MILC Collaboration calculation of electromagnetic effects on light pseudoscalar mesons. The simulations employ asqtad staggered dynamical quarks in QCD plus quenched photons, with lattice spacings varying from 0.12 to 0.06 fm. Finite volume corrections for the MILC realization of lattice electrodynamics have been calculated in chiral perturbation theory theory and applied to...Go to contribution page
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Dr Mateusz Koren (IFT UAM-CSIC Madrid)27/06/2014, 14:35We analyze 2+1 dimensional Yang-Mills theory regularized on a lattice with twisted boundary conditions in the spatial directions. In previous work it was shown that the observables in the non-zero electric flux sectors obey the so-called x-scaling, i.e. depend only on the variable x~NL/b and the magnetic flux, given by the parameters of the twist (L being the length of the spatial torus and b...Go to contribution page
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Mr Rehan MALAK (Mr)27/06/2014, 14:35TalkFor the Budapest-Marseille-Wuppertal collaboration. We present preliminary lattice QCD results for the leading-order hadronic contribution to the muon anomalous magnetic moment. Computations are based on 2+1 flavour simulations with HEX-smeared clover fermions and pion masses down to its physical value. Besides the traditional approach, several methods implementing derivatives of the...Go to contribution page
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Dr Michael Buchoff (Institute for Nuclear Theory)27/06/2014, 14:35One intriguing coincidence in cosmology is that the observed dark matter and baryonic densities are within a factor of 5 in magnitude. A natural explanation for such a coincidence is that the origin of the dark matter density is intimately related to the early universe processes that led to the baryon asymmetry. Many of these “asymmetric” dark matter scenarios favor a strongly coupled...Go to contribution page
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Dr Roberto Pellegrini (College of Science, Swansea University, Swansea, SA2 8PP, UK)27/06/2014, 14:35We present a novel algorithm to compute the density of states, which is proven to converge to the correct result. The algorithm is very general and can be applied to a wide range of models, in the frameworks of statistical mechanics and lattice gauge theory. All the thermal or quantum expectation values can then be obtained by a simple integration of the density of states. As an...Go to contribution page
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Prof. Lucini Biagio (Swansea University)27/06/2014, 14:55Recently, a new and efficient algorithm (the LLR method) has been proposed for computing density of states in statistical systems and gauge theories. In this talk, we explore whether this novel density of state method can be applied to numerical computations of observables in systems for which the action is complex. To this purpose, we introduce a generalised density of states, in terms of...Go to contribution page
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Mr Hanno Horch (University of Mainz)27/06/2014, 14:55TalkWe compute the Adler function from vacuum polarization data with twisted boundary conditions using numerical derivatives. The study is based on CLS ensembles with two flavours of O(a) improved Wilson fermions. To describe the momentum dependence and to extrapolate the lattice data to the continuum limit and to the physical point, we perform a combined fit and compare our results for the...Go to contribution page
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Dr Renwick Hudspith (York University)27/06/2014, 14:55We provide details of our implementation of a non-linear conjugate gradient method for Landau and Coulomb gauge fixing with Fourier acceleration. We find clear improvement over the Fourier accelerated steepest descent method, with the average time taken for our algorithm to converge to a fixed, high accuracy, being lower by a factor of 2 to 4 for several lattice volumes.Go to contribution page
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Dr Santanu Mondal (Eotvos University, Institute for Theoretical Physics, Budapest 1117, Hungary)27/06/2014, 14:55The strongly coupled near-conformal gauge theory with two fermion flavors in the two index symmetric (sextet) representation of the SU(3) color gauge group is the minimal realization of the composite Higgs mechanism. We discuss the baryon mass spectrum in this theory using staggered fermion operators to identify dark matter candidates.Go to contribution page
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Mr Venkitesh Ayyar (Duke University)27/06/2014, 14:55Massless fermions can become massive due to interactions through the mechanism of Spontaneous Symmetry Breaking (SSB). This mode of mass generation is popular and has been used in the Standard Model. Here, we explore the possibility of fermions acquiring a mass through interactions, but without SSB.\\ We consider a fermion system on a cubical lattice and introduce an on-site four-fermion...Go to contribution page
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Liuming Liu (University of Bonn)27/06/2014, 14:55Recently a charged resonance-like structure $Z_c(3900)$ has been observed in several experiments. The invariant mass of this structure is close to the DD* threshold, and one possible interpretation is a molecular bound state formed by the D and $\bar{D}*$ mesons. We study the low-energy scattering of $D\bar{D}^*$ using lattice QCD with N_f = 2 twisted mass fermion configurations with three...Go to contribution page
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Dr Axel Maas (University of Jena)27/06/2014, 14:55The Higgs sector of the standard model, the Higgs and the W/Z bosons, is a quite peculiar theory. Because of the Higgs effect, in some cases the observable particles, i.e. gauge-invariant bound states, have the same mass as the elementary particles. This is what makes perturbation theory in the electroweak sector possible. Under which condition this holds true is not only important for...Go to contribution page
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Dr Keitaro Nagata (KEK)27/06/2014, 15:15The Wilson fermion determinant can be written in the form of a series expansion in fugacity z=exp(mu/T), provided that the eigenmodes of the temporally reduced operator are obtained. Since the calculation of all eigenmodes rapidly becomes prohibitive for larger volumes, we develop a method to calculate only the low-energy eigenmodes of the reduced matrix using a matrix filetering...Go to contribution page
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Mr Luka Leskovec (Institute Jozef Stefan)27/06/2014, 15:15We perform a lattice QCD simulation of the charmonium-like channel, where experiments recently found several manifestly exotic states named Zc+ with flavor content bar c c bar d u. In addition to identifying all the scattering states we also observe an additional level in the simulation, which we attribute to Zc+.Go to contribution page
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Hans-Peter Schadler (University of Graz)27/06/2014, 15:15Generalized quark number susceptibilities have been proposed to be good probes for the phase transition in QCD and in the search of a critical point. In this work we explore the possibilities of the expansion in the fugacity parameter $e^{\mu\beta}$ which has features which make, in particular, quark number related bulk observables easily accessible. We will present results at finite chemical...Go to contribution page
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Dr Vincent Drach (CP3 Origins &amp; DIAS)27/06/2014, 15:15We investigate non perturbatively scattering properties of Goldstone Bosons in SU(2) gauge theory with two Wilson fermions in the fundamental representation. Such a theory can be used to build extensions of the Standard Model that unifies Technicolor and pseudo Goldstone composite Higgs models. The leading order contribution to the scattering amplitude of Goldstone bosons at low energy is...Go to contribution page
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Dr Pavel Buividovich (Regensburg University)27/06/2014, 15:15We study interacting Dirac fermions with chiral imbalance (modelled by a chiral chemical potential) in the mean-field approximation and find that the chiral imbalance is strongly enhanced due to spontaneous chiral symmetry breaking. We then consider the Chiral Magnetic Effect (CME) in the linear response approximation and find that in a phase with broken chiral symmetry the CME current is...Go to contribution page
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Gregorio Herdoiza (KPH Mainz and IFT Madrid)27/06/2014, 15:15TalkThe QCD contributions to the vacuum polarisation function are responsible for a large fraction of the theoretical uncertainty in the running of the QED coupling and therefore limit its impact on electroweak precision tests. We use lattice simulations with N_f=2 O(a) improved Wilson fermions to determine the Adler function in a broad range of momentum transfer Q^2. The running of the QED...Go to contribution page
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Dr Axel Cortes Cubero (City University of New York)27/06/2014, 15:15Massive Yang-Mills theory is known to be renormalizable in 1+1 dimensions. The gluon mass is introduced by coupling the gauge field to an SU(N) principal chiral nonlinear sigma model. The proof of renormalizability relies on the asymptotic freedom of the sigma model. However, renormalization forces the gluon mass to infinity. The continuum theory is in a confined phase rather than a Higgs...Go to contribution page
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Philippe de Forcrand (ETH Zurich)27/06/2014, 15:35We study the Hosotani mechanism on the lattice and show with the use of gauge invariant observables that SU(3) can break either to SU(2)xU(1) or U(1)xU(1). The novelty in this study is the strict gauge invariance of the observables used. We take advantage of the inability of a U(1) flux to decay in the continuum limit. One interesting consequence is that the SU(2) and U(1)...Go to contribution page
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Mr Matthew Spraggs (University of Southampton)27/06/2014, 15:35I demonstrate pyQCD, a native Python library providing an extensible API for single-node lattice measurements and simulations. Boost.Python is used to wrap the underlying C++ code and expose an interface to Python for the generation of propagators and configurations, both of which are returned as numpy ndarray types. The library can take advantage of GPU technology by using CUDA where possible...Go to contribution page
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Mr Simon Mages (University of Regensburg)27/06/2014, 15:35This talk is on recent efforts to determine the shear viscosity $\eta$ in the deconfined phase from lattice QCD. The main focus is on the integration of the Wilson flow in the analysis to get a better handle on the infrared behaviour of the spectral function which is relevant for transport. Also the non-perturbative renormalization strategy applied for the energy momentum tensor is discussed....Go to contribution page
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Ms Jana Günther (Bergische Universität Wuppertal)27/06/2014, 15:35Since the discovery of the Higgs particle at the LHC it is possible to investigate the equation of state for the electro weak transition in the SU(2)-Higgs-model at physical parameters. We will present a line of constant physics and preliminary results on the equation of state for small Nt values. The data was obtained by simulation with a combined heatbath and overrelaxation algorithm.Go to contribution page
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Christoph Lehner (BNL)27/06/2014, 15:35We explore ways to decrease parts of the finite volume error and apply the method to the hadronic contributions to muon g-2.Go to contribution page
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Mr Bartosz Kostrzewa (Humboldt Universität zu Berlin, Institut für Physik, Newstonstr. 15, 12489 Berlin, Germany / NIC, DESY, Zeuthen, Platanenallee 6, D-15738 Zeuthen, Germany)27/06/2014, 15:35In this contribution, updated results from simulations by the European Twisted Mass Collaboration at the physical point using Wilson twisted mass fermions with a clover term are presented. We discuss results for the pseudoscalar decay constants $f_K$, $f_D$ and $f_{D_s}$ and the corresponding masses. In addition, we provide evidence for a largely reduced flavour symmetry breaking in...Go to contribution page
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Daping Du (Syracuse University)27/06/2014, 16:30We update the lattice calculation of the $B\to\pi$ semileptonic form factors with a focus on the applications to the CKM matrix element $|V_{ub}|$. We use the MILC AsqTad 2+1-flavor lattice configurations at four lattice spacings and compute the matrix elements using the full-QCD valence quarks. We extrapolate the lattice data to continuum physics using the staggered chiral perturbation theory...Go to contribution page
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Dr James Zanotti (University of Adelaide)27/06/2014, 16:30TalkBy introducing an external spin operator to the fermion action, the quark-line connected matrix elements relevant for quark spin fractions of hadrons are extracted from the linear response of the hadron energies using the Feynman-Hellmann (FH) theorem. At the SU(3)-flavour symmetry point, we find that the connected quark spin fractions are universally in the range 55-70% for vector mesons...Go to contribution page
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Dr Jeff Greensite (San Francisco State University)27/06/2014, 16:30I explain the “relative weights” strategy for deriving effective Polyakov line actions, at finite chemical potentials, from the underlying lattice gauge theories. Gauge-Higgs and heavy quark models are the examples considered. The effective Polyakov line theories still have a severe sign problem, and I compare results obtained using mean field and complex Langevin methods to solve such theories.Go to contribution page
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Dr pietro giudice (University of Muenster)27/06/2014, 16:30We summarize the last results of our collaboration concerning N=1 supersymmetric Yang-Mills theory in four dimensions on the lattice. We investigate the expected formation of supersymmetric multiplets of the lightest particles and the behaviour of the topological susceptibility approaching the supersymmetric and the continuum limit of the theory.Go to contribution page
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Mr Jakob Simeth (University of Regensburg)27/06/2014, 16:30The quantification and subtraction of hypercubic lattice artifacts is essential for the calculation of non-perturbative renormalization constants. It has been shown that for the RI'-MOM scheme a large part of these artifacts can be calculated using Lattice Perturbation Theory (LPT), but these calculations are typically restricted to 1-loop order and to bilinear quark operators with one...Go to contribution page
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Dr Michele Brambilla (Università di Parma and INFN)27/06/2014, 16:50In recent years Numerical Stochastic Perturbation Theory (NSPT) has proven to be a viable tool to perform perturbative computation at high order on the lattice. Despite final results are equivalent to standard Feynman diagrams the approach is rather different and allows a numerical implementation similar to usual (nonperturbative) MonteCarlo. I will discuss final results for the computation...Go to contribution page
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Mr DANIEL ROBAINA (Institute of Nuclear Physics. Johannes Gutenberg University Mainz)27/06/2014, 16:50We investigate the low-temperature phase of QCD and the crossover region with two light flavors of quarks. The chiral expansion around the point $(T, m_q = 0)$ in the temperature vs. quark-mass plane indicates that a sharp real-time excitation exists with the quantum numbers of the pion. We determine its dispersion relation and test the applicability of the chiral expansion. The time-dependent...Go to contribution page
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Raza Sufian (University of kentucky)27/06/2014, 16:50TalkWe present a lattice QCD calculation of the glue helicity $\Delta G$ in the nucleon for the first time. It is recently shown that the first moment of the glue helicity distribution can be obtained through the product of the the electric field $\vec{E}$ and the gauge field in the Coulomb gauge $\vec{A}_C$, i.e. $\vec{E} \times \vec{A}_C$ in the infinite momentum frame. We used the gauge...Go to contribution page
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Prof. Makoto Sakamoto (Kobe University)27/06/2014, 16:50We propose a lattice model of a complex SUSY quantum mechanics which realizes the non-renormalization theorem on lattice. In our lattice model, the Leibniz rule in the continuum, which cannot hold on lattice due to a no-go theorem, is replaced by the cyclic Leibniz rule (CLR) for difference operators. It is shown that the CLR allows two of four supercharges of the continuum theory to preserve...Go to contribution page
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Dr Taichi Kawanai (Brookhaven National Laboratory)27/06/2014, 16:50We report results for the B→π and B_s→K semileptonic form factors using lattice QCD with domain-wall light quarks and relativistic b-quarks. We use the 2+1 flavor domain-wall Iwasaki gauge configurations generated by the RBC and UKQCD collaborations at two lattice spacings of a~0.08fm and a~0.11fm. Our lightest pion mass is about 290MeV. We perform the chiral and continuum extrapolations using...Go to contribution page
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Dr Michael Glatzmaier (University of Kentucky)27/06/2014, 17:10We discuss recent preliminary results for a lattice calculation of the glue helicity $\Delta_G$ in the Coulomb gauge. We have used the gauge field tensor defined from the overlap Dirac operator. The calculation is carried out with valence overlap quarks on 2+1 DWF gauge configurations on the $24^3 \times 64$ lattice which corresponds to a pion mass of 330 MeV. Finally, we discuss the...Go to contribution page
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Michael Engelhardt (New Mexico State University)27/06/2014, 17:10TalkLattice QCD calculations of transverse momentum-dependent parton distributions (TMDs) in a nucleon are performed based on a definition of TMDs via hadronic matrix elements of quark bilocal operators containing staple-shaped gauge connections. A parametrization of the matrix elements in terms of invariant amplitudes serves to cast them in the Lorentz frame preferred for the lattice...Go to contribution page
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Mr Lorenzo Riggio (INFN)27/06/2014, 17:10We present a lattice QCD determination of the vector and scalar form factors of the kaon semileptonic decay K->pi nu l , and of the D meson semileptonic decays D->(K/pi) nu l which are relevant for the extraction of the CKM matrix element |Vus|, |Vcd| and |Vcs| from experimental data. Our preliminary results are based on the gauge configurations produced by the European Twisted Mass...Go to contribution page
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Dr Yuzhi Liu (University of Colorado, Boulder)27/06/2014, 17:10We study the SU(4) lattice gauge theory with Nf=2 Dirac fermions in the anti-symmetric two index (sextet) representation (the ``SU(4)/sextet" theory). This is a real fermion representation, which allows simulation at non-zero chemical potential with no sign problem. In addition, ``SU(4)/sextet'' is an interesting generalization of QCD, allowing direct exploration of an alternate large-N_c...Go to contribution page
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Mr Andrey Kotov (ITEP, Moscow)27/06/2014, 17:10We present preliminary results of the study lattice SU(2) QCD phase diagram with chiral chemical potential. The simulation is carried out with dynamical staggered fermions without rooting. The dependences of the chiral density, Polyakov loop, chiral condensate and corresponding susceptibilities on the chiral chemical potential and temperature are measured.Go to contribution page
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Mr Oleg Kochetkov (University of Regensburg)27/06/2014, 17:30We study the influence of an external magnetic field on the deconfinement transition in two-flavour lattice QCD with physical quark charges. We use dynamical overlap fermions without any approximation such as fixed topology and perform simulations on a 16^3×6 lattice and at a pion mass around 500 MeV. The pion mass (as well as the lattice spacing) was determined in the independent runs on...Go to contribution page
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Mr Jacob Finkenrath (University of Wuppertal)27/06/2014, 17:30Most of today's lattice simulations are performed in the isospin symmetric limit in the light quark sector. A technique with moderate numerical cost to include effects of isospin breaking in the sea quark sector is mass reweighting. We will give a summary of the recent results on fine lattices with light quark masses. In general reweighting corrects the weight of an ensemble which is...Go to contribution page
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Dr Kei-ichi Nagai (KMI, Nagoya University)27/06/2014, 17:30We (LatKMI Collaboration) present the first observation of a flavor-singlet scalar meson as light as the pion in Nf=8 QCD on the lattice, using the HISQ action. Such a light scalar meson can be regarded as a composite Higgs with mass 125 GeV, and may be a technidilaton, a pseudo Nambu-Goldstone boson of the approximate scale symmetry in walking technicolor. We also report the update about...Go to contribution page
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Jonathan Flynn (University of Southampton)27/06/2014, 17:30TalkWe discuss nonperturbative renormalisation of the leading-twist flavour non-singlet operators needed for the calculation of the first and second moments of light-meson distribution amplitudes. On the lattice we use a regularisation-independent symmetric (or non-exceptional) momentum scheme, RI/SMOM, which, for the second moment, allows us to include mixing with a total-derivative operator. We...Go to contribution page
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Heechang Na (University of Utah)27/06/2014, 17:30We present our recent results on B to D, Bs to Ds, and Bs to K Standard Model tree level semileptonic decays. We have used MILC Nf=2+1 asqtad gauge configurations with two lattice spacings. For the valence quarks, we used NRQCD bottom quarks and HISQ light and charm quarks. The B to D and Bs to Ds semileptonic form factors can be used for better determination of the Bs to [mu^+ mu^-]...Go to contribution page
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Dr Akaki Rusetsky (HISKP, University of Bonn)27/06/2014, 17:50Using the non-relativistic effective field theory framework in a finite volume, we discuss the extraction of the $\Delta N\gamma^*$ transition form factors from lattice data. A counterpart of the L\"uscher approach for the matrix elements of unstable states is formulated. In particular, we thoroughly discuss various kinematic settings, which are used in the calculation of the above matrix...Go to contribution page
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Mr Hiroshi Ohki (Kobayashi-Maskawa Institute for the Origin of particles and the universe)27/06/2014, 17:50In the search for a composite Higgs boson in walking technicolor models, many flavor QCD is an attractive candidate. Particularly promising is the Nf=8 theory, which has been found to have a composite flavor-singlet scalar as light as the pion. Based on simulations of this theory with the HISQ action at various fermion masses in the LatKMI collaboration, we will present our preliminary results...Go to contribution page
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Jon Bailey (Seoul National University)27/06/2014, 17:50The CKM matrix element |V_{cb}| can be extracted by combining experimentally determined branching fractions for B to D(*) ell nu decays with form factors from the lattice. While successful, the precision of this approach has been limited by heavy-quark discretization effects. An improved version of the Fermilab action, the Oktay-Kronfeld action, can be used to reduce heavy-quark...Go to contribution page
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Mr Marco Mariti (University of Pisa & INFN)27/06/2014, 17:50We present improved results regarding our determination of the magnetic susceptibility in QCD. We discuss also preliminary data on higher order terms contributions in B to the free energy and to the relative increase in the pressure.Go to contribution page
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Prof. Haralambos (Haris) Panagopoulos (Univeristy of Cyprus)27/06/2014, 17:50We compute the difference in the renormalization of flavor singlet and nonsinglet fermion bilinear operators, to 2 loops in perturbation theory. Our results are applicable to a rather wide class of lattice actions with Symanzik improved gluons, stout links and clover fermions, including the Twisted Mass and SLiNC actions.Go to contribution page
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Ludmila Levkova (University of Utah)27/06/2014, 18:10We present results for the pressure of the quark-gluon plasma in the presence of a strong magnetic filed, calculated using a Taylor expansion in the field to 4th order. Our method does not require quantization of the magnetic filed and is computationally cheaper than calculations on ensembles generated with explicit magnetic fields.Go to contribution page
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Vittorio Lubicz (Universita' Roma Tre)27/06/2014, 18:10We describe our study of the chromomagnetic operator O_CM, which appears in the effective Hamiltonian describing DS=1 transitions in and beyond the Standard Model. Having dimension 5, the chromomagnetic operator is characterized by a rich pattern of mixing with other operators of equal and lower dimensionality. We have computed the coefficients of the mixing with the various dimension 5...Go to contribution page
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Mr Attila Nagy (Humboldt University Berlin)27/06/2014, 18:10We investigate the impact of a $\lambda_6 \pi^6$ term included in a chiral invariant lattice Higgs-Yukawa model. Such a term could emerge from BSM physics at some larger energy scale. We map out the phase structure of the Higgs-Yukawa model with positive $\lambda_6$ and negative quartic self coupling. To this end, we evaluate the constraint effective potential in lattice perturbation...Go to contribution page
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Michael G Endres (MIT)27/06/2014, 18:10Numerical studies of quantum theories usually rely upon an accurate determination of stochastically estimated correlation functions in order to extract information about the spectrum of the theory and matrix elements of operators. The reliable determination of such correlators is often hampered by an exponential degradation of signal/noise at late time separations. I will demonstrate that it...Go to contribution page
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Prof. Massimo D'Elia (University of Pisa & INFN)28/06/2014, 08:30Talk
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Prof. Tilo Wettig (University of Regensburg)28/06/2014, 09:00TalkI will give an overview of QPACE 2, which is a custom-designed machine based on Intel Xeon Phi processors, developed by Regensburg University in collaboration with Eurotech (Italy/Japan). I will also discuss our high-performance implementation of a domain-decomposition-based solver on the Xeon Phi and present benchmarks of its strong-scaling behavior.Go to contribution page
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Prof. Masakiyo Kitazawa (Osaka University)28/06/2014, 09:30We propose a novel method to define and calculate the energy-momentum tensor (EMT) in lattice gauge theory on the basis of the Yang-Mills gradient flow. Using this method, we measure the thermodynamics of SU(3) gauge theoy on fine lattices with lattice size up to 64^3x18. The numerical results with small lattice spacing confirm our previous findings; the expectation values of the EMT...Go to contribution page
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Prof. Chris Sachrajda (University of Southampton)28/06/2014, 10:30Talk
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28/06/2014, 11:15
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Lat14 Test (BNL)
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