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Dr
Donald Sinclair
(Argonne National Laboratory)
23/06/2014, 14:15
Physics Beyond the Standard Model
Talk
We 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.
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Ms
Cynthia Yu-Han Huang
(National Chiao-Tung University, Taiwan)
23/06/2014, 14:35
Physics Beyond the Standard Model
Talk
We 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...
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Dr
Hideo Matsufuru
(High Energy Accelerator Research Organization (KEK))
23/06/2014, 14:55
Physics Beyond the Standard Model
Talk
We 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.
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Mr
Tiago Jose Nunes da Silva
(University of Groningen)
23/06/2014, 15:15
Physics Beyond the Standard Model
Talk
We 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...
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Mr
Oscar Akerlund
(ETH Zurich)
23/06/2014, 15:35
Physics Beyond the Standard Model
Talk
We 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...
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Dr
Julius Kuti
(U.C. San Diego)
23/06/2014, 16:30
Physics Beyond the Standard Model
Talk
We 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.
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Mr
chik him wong
(University of California, San Diego)
23/06/2014, 16:50
Physics Beyond the Standard Model
Talk
The 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.
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Dr
Enrico Rinaldi
(Physics Division, Lawrence Livermore National Laboratory)
23/06/2014, 17:10
Physics Beyond the Standard Model
Talk
Composite 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...
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Mr
Evan Weinberg
(Boston University)
23/06/2014, 17:30
Physics Beyond the Standard Model
Talk
The 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...
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Dr
Graham Moir
(University of WUppertal)
23/06/2014, 17:50
Physics Beyond the Standard Model
Talk
We 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...
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Dr
Ari Hietanen
(CP3-Origins, SDU)
23/06/2014, 18:10
Physics Beyond the Standard Model
Talk
We 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...
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Mr
Maxwell Hansen
(University of Washington)
24/06/2014, 14:15
Physics Beyond the Standard Model
Talk
We 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...
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Dr
Andrea Shindler
(Forschungszentrum Jรผlich)
24/06/2014, 14:35
Physics Beyond the Standard Model
Talk
With 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...
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Prof.
Anna Hasenfratz
(University of Colorado Boulder)
25/06/2014, 09:00
Physics Beyond the Standard Model
Talk
The 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...
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Dr
Jarno Rantaharju
(Riken Advanced Institute for Computational Science)
25/06/2014, 09:20
Physics Beyond the Standard Model
Talk
We 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.
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Prof.
C.-J. David Lin
(National Chiao-Tung University, Taiwan)
25/06/2014, 09:40
Physics Beyond the Standard Model
Talk
We 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...
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Prof.
Luigi Del Debbio
(University of Edinburgh)
25/06/2014, 10:00
Physics Beyond the Standard Model
Talk
The 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...
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Dr
Joyce Myers
(Niels Bohr Institute)
25/06/2014, 10:20
Physics Beyond the Standard Model
Talk
We 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...
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Mr
Stefano Piemonte
(WWU Mรผnster)
25/06/2014, 11:10
Physics Beyond the Standard Model
Talk
The behaviour of supersymmetric theories at ๏ฌnite 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 ๏ฌnite temperatures. This model is the simplest supersymmetric...
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Dr
ANOSH JOSEPH
(Deutsches Elektronen-Synchrotron DESY)
25/06/2014, 11:30
Physics Beyond the Standard Model
Talk
Certain 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...
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Urs Wenger
(University of Bern)
25/06/2014, 11:50
Physics Beyond the Standard Model
Talk
The 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...
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Prof.
Simon Catterall
(Syracuse University)
25/06/2014, 12:10
Physics Beyond the Standard Model
Talk
N=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...
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Joel Giedt
(Rensselaer Polytechnic Institute)
25/06/2014, 12:30
Physics Beyond the Standard Model
Talk
We 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...
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David Schaich
(Syracuse University)
25/06/2014, 12:50
Physics Beyond the Standard Model
Talk
I 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...
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Dr
William Detmold
(MIT)
27/06/2014, 14:15
Physics Beyond the Standard Model
Talk
We 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...
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Dr
Michael Buchoff
(Institute for Nuclear Theory)
27/06/2014, 14:35
Physics Beyond the Standard Model
Talk
One 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 โasymmetricโ dark matter scenarios favor a strongly coupled...
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Dr
Santanu Mondal
(Eotvos University, Institute for Theoretical Physics, Budapest 1117, Hungary)
27/06/2014, 14:55
Physics Beyond the Standard Model
Talk
The 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.
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Dr
Vincent Drach
(CP3 Origins & DIAS)
27/06/2014, 15:15
Physics Beyond the Standard Model
Talk
We 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...
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Philippe de Forcrand
(ETH Zurich)
27/06/2014, 15:35
Physics Beyond the Standard Model
Talk
We 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)...
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Dr
pietro giudice
(University of Muenster)
27/06/2014, 16:30
Physics Beyond the Standard Model
Talk
We 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.
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Prof.
Makoto Sakamoto
(Kobe University)
27/06/2014, 16:50
Physics Beyond the Standard Model
Talk
We 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...
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Dr
Yuzhi Liu
(University of Colorado, Boulder)
27/06/2014, 17:10
Physics Beyond the Standard Model
Talk
We 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...
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Dr
Kei-ichi Nagai
(KMI, Nagoya University)
27/06/2014, 17:30
Physics Beyond the Standard Model
Talk
We (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...
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Mr
Hiroshi Ohki
(Kobayashi-Maskawa Institute for the Origin of particles and the universe)
27/06/2014, 17:50
Physics Beyond the Standard Model
Talk
In 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...
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Mr
Attila Nagy
(Humboldt University Berlin)
27/06/2014, 18:10
Physics Beyond the Standard Model
Talk
We 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...
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