Dark Interactions: Perspectives from Theory and Experiment

4 Oct 2016, 09:00 → 7 Oct 2016, 14:14 US/Eastern

Physics Department, Bldg. 510, Large Seminar Room (Brookhaven National Laboratory)

Ketevi Adikle Assamagan (BNL)

Back to Workshop

To review and discuss the status and future of the searches for dark vector bosons, such as the dark Z, with interpretation for Dark Matter.

Topics or Session Information:

• Theoretical motivation for dark vector bosons
• Constraints from low energy experiments
• Input from LHC Run 1
• Interpretation for Dark Mark
• Prospects for LHC Run 2 and low energy experiments

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Tuesday, 4 October

09:00 → 09:10 Workshop Opening

Opening address and information for the participants

Speaker: William Marciano (BNL)

Slides welcome.pdf

09:10 → 12:40 Overview of light dark sectors

Convener: Hooman Davoudiasl (Brookhaven National Laboratory)

09:10 Theoretical motivation and phenomenology of light dark sectors

Speaker: Joerg Jaeckel (Heidelberg)

Slides JoergJaeckel.pdf

10:00 Axions and ultralight dark photons: theory+searches

Speaker: Sergei Dubovsky (New York University)

Slides photon_axion.key.pdf

10:50 Discussion

11:00 Break

11:30 Dark photons at MeV-GeV masses

Speaker: Natalia Toro (SLAC)

Slides 2016-10-04Brookhaven-NataliaToro.pdf

12:20 Discussion

12:30 → 13:50 Lunch

13:50 → 15:30 MeV-GeV dark matter

Convener: Rouven Essig (Stony Brook University)

13:50 Theory + electron beam dumps

Speaker: Eder Izaguirre (BNL)

Slides BNLDarkInteractionsOct2016.pdf

14:20 Proton beam dumps (MiniBoone, Seaquest, SHIP)

Speakers: Brian Batell (Chicago), Mr Brian Batell (Perimeter Institute)

14:50 Direct Detection

Speaker: Tien Tien Yu

Slides BNL_DI_Oct2016.pdf

15:20 Discussion

15:30 → 16:00 Break

There will be coffee and cookies in Berkner lobby starting at 3:30, so the coffee break will be in Berkner Lobby.

16:00 → 17:00 BSA Distinguished lecture

16:00 Dark Matter / Dark Interaction

Speaker: Hitoshi Murayama (Berkeley)

17:00 → 18:00 BSA Distinguished Lecture Reception

Wednesday, 5 October

09:00 → 10:10 Dark Sectors at Colliders 1

Convener: Oliver Keith Baker (Yale University)

09:00 Dark Matter searches at the LHC

Speaker: Antonio Boveia

Slides 20161005_Dark_Interactions.pdf

09:40 Dark sector searches at e+e- colliders

Speaker: Yury Kolomensky (LBL)

Slides DarkPhoton-DI2016.pdf

10:00 Discussion

10:10 → 10:40 Break

10:40 → 12:30 Dark Sectors at Colliders 2

Convener: Oliver Keith Baker (Yale University)

10:40 Decays to dark sector particles at CMS

Speaker: Ted Kolberg

Slides DI2016_tkolberg.pdf

11:30 Decays to dark sector particles at ATLAS

The postulation of a Hidden Sector to complement the Standard Model offers elegant solutions to one of the most intriguing questions in elementary particle physics, being the particle nature of dark matter. The discovery of a fundamental scalar particle compatible with the Higgs boson paved the way for looking for dark matter with novel methods. In this contribution, I will review recent searches to dark sector particles performed by the ATLAS collaboration. Particular emphasis will be given to results with recent proton-proton data at 13-TeV center-of-mass energy, to improvements in the trigger and reconstruction of physics objects that happened during the LHC long shut-down and to prospects for results with the enlarged dataset being collected by the experiment this year.

Speaker: Andrea Coccaro

Slides AndreaCoccaro.pdf

12:20 Discussion

12:30 → 14:00 Lunch

14:00 → 16:05 Dark Matter

Convener: Hitoshi Murayama (Berkeley)

14:00 Status of Dark Matter Direct Detection

Speaker: Ethan Brown (RPI)

Slides DirectDetectionStatus_DarkInteractions_Brown.pdf

14:40 Dark Photon Search at the Fermilab SeaQuest Experiment

The SeaQuest E906 experiment is a fixed target Drell-Yan experiment which is aimed at studying the anti-quark distributions in the nucleon and nuclei. 120 GeV protons from the Main Injector at Fermilab could also be used to search for massive dark gauge bosons or dark photons that could be generated when a proton beam dump interacts with a 5m long Fe beam dump. SeaQuest takes advantage of Proton Bremsstrahlung and \eta decay processes to search for dark photons that could provide a portal into the dark sector. Exclusion limit projections for SeaQuest and future prospects for the experiment will be discussed in the talk.

Speaker: Arun Tadepalli

Slides Dark_Interactions_2016_SeaQuest.pptx

15:00 Direct Search for Dark Photon and Dark Higgs in E-1067 at Fermilab

Through kinetic mixing, the postulated dark photon and dark Higgs particles could be produced in the Drell-Yan like q-qbar and gluon-gluon fusion processes in high energy proton + nucleus collisions, respectively. Starting from 2017, the E-1067 experiment at Fermilab will carry out the first direct search for such particle productions in the mass range 0.2 ~ 10 GeV in parasitic with the E906/SeaQuest experiment. LOI of E-1067 was first submitted to PAC in the summer of 2015 and subsequently endorsed by Fermilab director. In the near future, we also plan to install new EM calorimeters recycled from the PHENIX experiment at RHIC to add di-electron capability to the search thus allowing us to access the mass region below the current dimuon limit. To maximize the experimental reach, we are taking on a major upgrade of the SeaQuest DAQ and trigger systems now and will be ready for data taking in early 2017. In this talk, the current status of the upgrade projects and expected experimental reach will be presented.

Speaker: Ming Xiong Liu (Los Alamos National Laboratory)

Slides Fermilab-E1067-Dark-Interactions-BNL-102016-Liu.pdf

15:20 Discussion

15:30 → 16:00 Break

16:00 → 17:30 Cosmology and astrophysics

Convener: Prof. Chris S. Hill (The Ohio State University)

16:00 Latest Results from Cosmological probes

Speaker: Bhuvnesh Jain (UPenn)

Slides Brookhaven-2016-Jain.pdf

16:40 Gravitational Wave Signals of Cosmological Phase Transitions

Strong first-order cosmological phase transitions produce a stochastic gravitational wave background. We discuss the resulting contributions from bubble collisions, magnetohydrodynamic turbulence, and sound waves, and estimate the total corresponding signal predicted in gravitational waves. We demonstrate that LISA is able to probe many well-motivated scenarios beyond the Standard Model of particle physics predicting strong first-order cosmological phase transitions in the early Universe.

Speaker: Geraldine Servant (CERN)

Slides Brookhaven_2016.pdf

17:20 Discussion

17:45 → 21:30 Workshop Dinner

At the Majestic Gardens, Route 25A, Rocky Point, NY
http://majesticgardens.com/

Thursday, 6 October

09:00 → 10:30 Neutral naturalness, Hidden valley Dark Sectors

Convener: William Marciano (BNL)

slides fromGeraldine.pdf

09:00 Neutral naturalness

Speaker: Nathaniel Craig

Slides DarkInteractions_2016.pdf

09:40 Searches for Hidden Valleys at the LHC

Speaker: Matt Strassler (Harvard)

Slides Strassler_DarkInt.pdf

10:20 Discussion

10:30 → 11:00 Break

11:00 → 12:30 Neutrinos and hidden physics

Convener: Dr Mary Bishai (Brookhaven National Laboratory)

11:00 Astrophysical Probes of Neutrinos

Speaker: Alexander Friedland (SLAC National Accelerator Laboratory)

Slides Friedland_BNL_Oct6_2016.pdf

11:40 Neutrino anomalies

Speaker: Andre DeGouvea (Northwestern)

Slides DI_2016_degouvea.pdf

12:20 Discussion

12:30 → 14:00 Lunch

14:00 → 18:05 Contributed talks related to dark sectors/dark interactions

Each talk (15+5) min with a 30 min break in the afternoon

Conveners: Dr Ketevi Adikle Assamagan (BNL), Michael Begel (Brookhaven National Lab)

14:00 Recent results and prospects on Dark Interactions from CERN

Kaon experiments at CERN (NA48/2 and NA62) study decays in flight of secondary charged kaons produced by 400 GeV/c protons from the SPS accelerator hitting a Beryllium target. The NA48/2 experiment was exposed to 2x10^{11} kaon decays in 2003-2004, and NA62 is set to surpass this figure by a factor of 50 in 2016-2018. Prospects for the dark photon, heavy neutral lepton and axion-like particle searches via their production (both promptly at the Beryllium target and in secondary kaon decays) and decay with available and future NA62 data are discussed. Results of searches for the dark photon, inflaton and heavy neutral leptons in charged kaon and neutral pion decays with NA48/2 data are presented.

Speaker: Gianluca Lamanna

Slides lamanna_di2016.pdf

14:20 Simplified DM models: a case with t-channel colored scalar mediators

The general strategy for dark matter (DM) searches at colliders currently relies on simplified models in order to describe the interactions between the Standard Model (SM) and DM and potential collider signatures at the LHC. A recently proposed UV-complete simplified model with t-channel mediators improves the existing simplified DM models in two important respects: (i) the full SM gauge symmetry is imposed including the fact that the left-handed and the right-handed fermions have two independent mediators with two independent couplings, and (ii) the renormalization group evolution is included in the effective Lagrangian for DM-nucleon scattering when integrating out the t-channel mediators. The first improvement will introduce a few more parameters compared with the existing simplified DM models. The effect this broader set of free parameters has on direct detection and the mono-X + MET (X=jet,W,Z) signatures at 13 TeV LHC are discussed.

Speaker: Alexander Natale (KIAS)

Slides ACN-DI-2016.pdf

14:40 Dark matter models with two mediators

A reliable comparison of different dark matter searches requires models that satisfy certain consistency conditions like gauge invariance and perturbative unitarity. These conditions can easily be satisfied in U(1)' extensions of the Standard Model, where a fermionic dark matter candidate as well as a new Z' gauge boson obtain their mass from the spontaneous breaking of the U(1)' by a dark Higgs. These dark matter scenarios contain two mediators, the new gauge boson and the dark Higgs, which can also act as final states in dark matter annihilation. I will discuss the general framework of consistent dark matter models with two mediators, and then review a class of dark matter models where baryon number is a local gauge symmetry.

Speaker: Michael Duerr (DESY)

Slides DarkInteractions2016_duerr.pdf

15:00 Search for Dark Particles at Belle and Belle II

The dark photon, A′, the dark Higgs boson, h′, and the dark vector gauge boson, U', are hypothetical constituents featured in a number of recently proposed Dark Sector Models. We will present searches for these particles in the Belle data and discuss prospects in the future Belle II data.

Speaker: Igal Jaegle (University of Hawaii at Manoa)

Slides igaljaegle_darkinteractions2016.pdf

15:20 Search for Dark Photons at LHCb

Dark photons appear in many well-motivated dark matter scenarios, leading to a worldwide effort to search for them. We propose some novel search methods for dark photons at the LHCb experiment. In this talk, I will focus on the inclusive search for dark photons at the LHCb experiment based on both prompt and displaced di-muon resonances. The dark photon rate can be directly inferred from the off-shell photon rate, making this a fully data-driven search. LHCb is applying this method for the dark photon search in the Run 2 of LHC. For Run 3, LHCb will have sensitivity to large regions of the unexplored dark photon parameter space.

Speaker: Wei Xue (MIT)

Slides DarkPhoton_darkinteraction.pdf

15:40 Break

16:15 Astrophysical Signatures of Dissipative Dark Matter

After nearly a century of searching, the nature of dark matter continues to elude us.While Ockham's razor may at face value want a favor a dark sector with one component, the complexity of the visible sector urges us to consider dark sectors with multiple components, including possibly dissipative interactions. In a galaxy like the Milky Way, these interactions would lead to cooling of the dissipative sector, resulting in a disk of dark matter with enhanced local density. I will briefly review the current bounds on the local dark matter density and explain why they do not apply to a dark disk. I will then explain what the latest astrophysical data truly say about a dark disk, including the bounds we recently determined from Milky Way stellar kinematics and from the distribution of the local interstellar gas, and what we can expect in upcoming the Gaia era.

Speaker: Eric Kramer (Harvard University)

Slides kramer_di2016.pdf

16:35 Updated Bounds on Light Hidden Sectors in Supernovae

Supernova 1987A created an environment of extremely high temperatures and nucleon densities, providing an opportunity to set bounds on a wide range of theories of new physics. We present corrected bounds on hidden sector models, incorporating a wide range of new physical effects on the production, including some novel corrections to the high-mixing-angle calculation. These bounds dramatically alter the landscape of the allowed regions for hidden sector models.

Speaker: Samuel McDermott (YITP)

Slides sn-talk.pdf

16:55 "Lattice Gauge Theory insights on Dark Matter

Models of composite dark matter, originating from a new strongly coupled dark sector, have a very interesting phenomenology. To make robust predictions in these models one often need to investigate non-perturbative effects due to the strong self interactions. Lattice field theory methods and numerical simulations are well suited for this task and contribute to a solid uncertainty quantification. As an example, the Stealth Dark Matter model contains a candidate composite dark matter particle which appears as a bosonic neutral baryon of a new SU(4) strongly coupled gauge sector. The elementary constituents of this composite state carry electroweak charges. This construction provides a mechanism to naturally reduce the strength of dark matter interactions with standard model particles: there is no magnetic moment or charge radius. However such interactions exist and can allow direct detection and collider experiments to put constraints on the model. In order to get predictions from this strongly-coupled model, numerical lattice simulations are employed and give definite results for the cross-section of the dark matter candidate with standard nuclei in detectors, dominated by the electric polarizability interaction. A universal lower bound for the mass of this composite dark matter candidate is reported around 300 GeV.

Speaker: Enrico Rinaldi (BNL)

Slides DarkMatter_Rinaldi_15min_v3.pdf

17:15 The search for a dark Z boson with Machine Learning

The existence of a dark sector vector boson (Zd) is well motivated by theory and experiment; models add a U(1) gauge symmetry to the standard model which introduces a new gauge field Zd with kinetic mixing epsilon (I'll add the actual symbol) and a Higgs doublet with mass mixing kappa. We can thus use the Higgs as a portal to look for such a particle at the LHC. In particular, we can expand upon the standard ATLAS H->4l analysis to search for and measure the properties of the Zd. I will describe the structure and current status of this analysis, as well as potential applications for using machine learning techniques to increase sensitivity.

Speaker: Savannah Thais (Yale University)

Slides dark_interactions_16_talk.pdf dark_interactions_16_talk.pptx

17:35 Respect the ELDERs

We present a novel dark matter candidate, an elastically decoupling relic, which is a cold thermal relic whose present abundance is determined by the cross section of its elastic scattering on standard model particles. The dark matter candidate is predicted to have a mass ranging from a few to a few hundred MeV, and an elastic scattering cross section with electrons, photons and/or neutrinos in the 10^{-3} – 1  fb range..

Speaker: Yu-Dai Tsai (Cornell University)

Slides ELDER_Yu-Dai_Tsai_DI-2016_final_submit.pdf

18:10 → 19:40 Workshop Reception

Friday, 7 October

09:00 → 10:30 The Future at the very large and the very small scales I

Convener: Rouven Essig (Stony Brook University)

09:00 Future prospects in cosmology

Speaker: Raphael Flauger (University of Texas at Austin)

Slides 161005.pdf

09:40 Physics at Future Circular Colliders

The Large Hadron Collider has been a grand success with the discovery of the Higgs boson, with bright prospects for additional discoveries since the recent increase in collider energy and the anticipated large datasets. Big open questions such as the nature of dark matter, the origin of the matter-antimatter asymmetry in the Universe, and the theoretical puzzle of the finely-tuned parameters in the Higgs sector, demand new physics principles that extend the established Standard Model paradigm. Future circular colliders in a substantially larger tunnel can house both a high luminosity electron-positron collider for precision measurements of Higgs and electroweak parameters, as well as a very high energy proton-proton collider which can directly manifest particles associated with these new physics principles. We discuss the physics goals of these future circular colliders, and the prospects for elucidating fundamental new laws of nature that will significantly extend our understanding of the Universe. Detailed studies of the discovery potential in specific benchmark models will be presented, with implications for detector design.

Speaker: Prof. Ashutosh Kotwal (Duke University)

Slides kotwal-bnl2016.pdf

10:20 Discussion

10:30 → 11:00 Break

11:00 → 11:45 The Future at the very large and the very small scales II

Convener: Hooman Davoudiasl (Brookhaven National Laboratory)

11:00 The Status of Primordial Black Holes as Dark Matter

Speaker: Ely Kovetz (John Hopkins University)

Slides Ely.David.Kovetz.pdf

11:35 Discussion

11:45 → 12:00 General Discussion

Speaker: ALL

12:00 → 12:15 Acknowledgements and Thanks

Convener: Dr Ketevi Adikle Assamagan (BNL)

Group Photo D1581016.jpg

12:15 → 13:59 Lunch

13:59 → 14:00 Workshop Ends