***ATTENTION Indico Users***

Important changes to user logins are coming to Indico at BNL.

Please see the News section for more information.

Dark Interactions: Perspectives from Theory and Experiment

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

Physics Department, Bldg. 510, Large Seminar Room

Brookhaven National Laboratory

Ketevi Adikle Assamagan (BNL)
Description

Back to Workshop

To review and discuss the theoretical context as well as the status and future of the searches for dark sector particles, such as dark vector bosons, and the implications for dark matter.

Topics or Session Information:
  • Theoretical Motivation for Dark Sectors
  • Experimental Constraints from High Energy Colliders
  • Constraints from non-Collider Experiments
  • Cosmological Constraints
  • Implications for Dark Matter
  • Prospects for LHC Run 2 and future Intensity Frontier Experiments
pictures
Workshop Coordinator
    • 08:45 09:00
      Workshop Opening Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Opening address and information for participants

      Convener: Dr Howard Gordon (BNL)
      slides
    • 09:00 10:30
      Theoretical Motivation Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Theoretical motivation for dark interactions

      • 09:00
        Theoretical Motivation for New Weakly Coupled States (includes axions, sub-MeV dark photons, ALPs, etc.) 35m
        Speaker: Neal Weiner (NYU)
      • 09:40
        Theory and Phenomenology of Dark Vector Bosons 35m
        New physics can be light relative to the electroweak scale provided it couples very weakly to the Standard Model. An attractive and well-motivated example of this is a new dark vector boson. In this talk I will cover the theory of dark vectors with an emphasis on kinetic mixing with the photon and mass mixing with the Z boson. I will also touch briefly on the experimental implications of various dark vector models.
        Speaker: David Morrissey (TRIUMF)
        Slides
      • 10:20
        Discussion 10m
    • 10:30 11:00
      Break 30m Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

    • 11:00 12:30
      Low-energy Direct Searches for Dark Photons Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Convener: Rouven Essig (Stony Brook University)
      • 11:00
        Dark Light 15m
        The DarkLight experiment aims to search for a dark photon in the low mass region 10-100 MeV/c^2. By using the Jefferson Lab FEL’s high-intensity 100 MeV, 1 MW electron beam incident on a gaseous hydrogen target, the process ep -> ep,e+/e- will be studied. To search for a dark photon, full track reconstruction of the four-particle final state will be performed in order to observe a resonance on the e+/e- invariant mass spectrum. The design of a detector suited to this task and the status of its development will be presented.
        Speaker: Charles Epstein (MIT)
        Slides
      • 11:20
        APEX - The APrime EXperiment at Jefferson Lab 15m
        APEX is a fixed target experiment in Experimental Hall A at Thomas Jefferson National Accelerator Facility (JLab) in Virginia, USA, that is designed to search for a new gauge boson (A') with sub-GeV mass and coupling to ordinary matter of g'/e ~ (1 - 10^-4). Electrons impinge upon a fixed target of high-Z material to produce an A' via a process analogous to photon bremsstrahlung. The A' then decays to an e+e- pair that is detected by the JLab Hall A High Resolution Spectrometers. A test run was held in July of 2010, covering an A' mass range from 175 to 250 MeV and couplings g'/e > 10^-3. A full run is approved, with coverage projections of m_A' ~ 65 to 525 MeV and g'/e > 2.3 x 10^-4. The JLab accelerator facility is currently being upgraded to deliver 12 GeV beam. While the Hall A schedule has not yet been finalized, APEX will be ready to run soon after the completion of the upgrade and beam commissioning. I will present the results of the test run and report on the preparations for the full run.
        Speaker: James Beacham (New York University)
        Slides
      • 12:00
        Mainz MAMI 15m
        The A1 collaboration at the Mainz Microtron has concluded a pilot study in 2011 and data taking periods in 2012/2013 to search for a dark photon. The focus of the experiment was on the mass range between 50-200 MeV where dark matter provides a possible explanation for the discrepancy in the anomalous magnetic moment of the muon (g-2). The analysis is finished and the final exclusion limits will be presented. The Mainz search for a dark photon will continue as a part of the new MESA (Mainz Energy-recovering Superconducting Accelerator) project. In this talk, the present status of the detector and target design will be shown.
        Speaker: Michael Distler (University Mainz, Germany)
        Slides
      • 12:20
        Discussion 10m
    • 12:30 12:40
      Workshop Group Photo 10m Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

    • 12:40 14:00
      Lunch 1h 20m Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

    • 14:00 15:30
      Light (sub-GeV) Dark Matter Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Convener: Oliver Keith Baker (Yale University)
      • 14:00
        Theory motivation for sub-GeV DM + searches at proton beam dumps 25m
        Speaker: Brian Batell (University of Chicago)
        Slides
      • 14:30
        Electron Beam Dump Experiments 20m
        Speaker: Philip Schuster (Perimeter Institute)
        Slides
      • 14:55
        Direct Detection Prospects 20m
        Speaker: Jeremy Mardon (Stanford)
        Slides
      • 15:20
        Discussion 10m
    • 15:30 16:00
      Break 30m Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

    • 16:00 17:40
      Dark Bosons at e^+e^- Colliders, Meson Decays, and Parity Violation Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Convener: Marciano William (BNL)
      • 16:00
        Search for Dark Photons and Higgs at BaBar 15m
        Extensions to the Standard Model allow for new particles, including low-mass Higgs bosons and dark photons, that may bridge the Standard Model to the Dark Sector. We present recent results of searches for such particles in electron-positron annihilation with the BaBar Detector at the SLAC National Accelerator Laboratory. We also report briefly on a measurement of antideuteron production at BaBar, and comment on its significance for dark matter searches.
        Speaker: Prof. David Brown (University of Louisville)
        Slides
      • 16:20
        Belle/Belle II 15m
        We will present a new Belle (preliminary) limit in the search for a dark photon, A, and a dark Higgs, h', with A and h' prompt, mh' > 2mA, 100 MeV < mA < 3.5 GeV and 200 MeV < mh' < 10.5 GeV. We will also discuss possible future contributions of Belle II to dark sector particle searches.
        Speaker: Igal Jaegle (University of Hawaii at Manoa)
        Slides
      • 16:40
        Meson-Decay Experiments 15m
        The dark photon couples to Standard Model particles via kinetic mixing, so it may be produced in SM processes and decay to SM particles. Experiments that are designed for precise measurements of meson decay and detection of rare meson decay have high-resolution detectors and large data samples, making them well suited to search for dark photons. I will describe limits on dark photons from pion, kaon, and phi decay at SINDRUM, WASA-at-COSY, KLOE, NA48/2, NA62, and E787/949. I will also describe limits from electron-positron annihilation in KLOE.
        Speaker: Elizabeth Worcester (BNL)
        Slides
      • 17:00
        PHENIX Searches for Low Mass Dark Photons 15m
        Several theoretical models introduce an additional U(1) gauge boson, a "dark photon" which mixes with ordinary QED photons with very small mixing strength. The dark photon is considered as one of the strongest candidates to describe some astrophysical anomalies as well as the 3sigma deviation of the experimental muon g-2 value from the Standard Model calculation. The dark photon as the cause for the muon g-2 anomaly gets more important because of recent SUSY search result at the LHC. Recently the PHENIX experiment at RHIC searched for the dark photon in pi0 and eta Dalitz decays. With both a very good mass resolution of the PHENIX detector and a high statistics sample of pure e+e- pairs from Dalitz decays, we obtain the world's best upper limits on the dark photon mixing parameter space for m_U between 30 and 90 MeV/c^2. In this talk, the latest PHENIX result will be shown.
        Speaker: Yorito Yamaguchi (University of Tokyo)
        Slides
      • 17:20
        Muon g-2 and dark parity violation 15m
        Speaker: Dr Hye-Sung Lee (College of William and Mary / Jefferson Lab)
        Slides
    • 18:00 19:00
      Workshop Reception Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

    • 09:00 10:40
      Higgs Window into Dark Sectors Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Convener: Dr Ketevi Adikle Assamagan (BNL)
      • 09:00
        Exotic Higgs Decays (theory, various models) 20m
        Exotic Higgs decays may be our main window to new physics. They are common and often well-motivated in various new physics scenarios, partly due to the small natural width of the Higgs. Some exotic decay modes are cascades resulting in high multiplicity of the final state, and are therefore potentially spectacular. Still, they could easily be missed, partly due to triggering thresholds. This strongly suggests new dedicated experimental searches to be performed. I will review the motivation and show current and prospective estimated reach at LHC for a few exotic decay modes.
        Speaker: Ze'ev Surujon (Stony Brook University)
        Slides
      • 09:30
        Higgs decays to exotic particles at CMS 20m
        The results of searches for invisible decays of the Higgs boson in the vector boson fusion and associated ZH production modes, where Z decays to a pair of charged leptons or a bbbar quark pair, are presented. Searches performed using data collected in proton-proton collisions at center-of-mass energies of 7 TeV and 8 TeV by the CMS experiment at the LHC. With no excess of the observed data over the expected Standard Model backgrounds, limits on the production cross section times invisible branching fraction, as a function of the Higgs boson mass, are set. Assuming the Standard Model Higgs boson cross sections, the limit on the invisible branching fraction of the Higgs boson is set and interpreted in terms of Higgs-portal model of dark matter. In addition, a search for non-SM Higgs boson decays to a pair of new light bosons, each of which subsequently decays into a collimated pair of muons, is presented. The search is performed using data collected by the CMS experiment in proton-proton collisions at center-of-mass energies of 8 TeV. Results are interpreted in a model independent fashion applicable to a broad class of models predicting the same signature as well as in the context of the SUSY with hidden dark sector.
        Speaker: Aysen Tatarinov (Texas A&M University)
        Slides
      • 09:55
        Higgs decays to exotic particles at ATLAS 20m
        The discovery of a Higgs-like particle in ATLAS and CMS at the Large Hadron Collider opened a rich and interesting range of opportunities for discovery of exotic decays, i.e. decays that involve new light states beyond the SM. A large class of simplified and complete models gives rise to peculiar patterns of exotic decays of the Higgs boson, patterns that the ATLAS experiment is exploring with several dedicated analysis. The status of such searches in the data collected during the Run 1 of LHC, at center of mass energies of 7 and 8 TeV, will be reviewed, together with the perspectives for the new run at higher energy that will start in 2015. Particular emphasis will be given to the most recent results involving the direct search for invisible Higgs decays, and the indirect constraints on new phenomena obtained from coupling measurements of the Higgs boson, and the interpretation of these constraints in the context of the Higgs portal model to Dark Matter. Results of the searches performed in ATLAS for decays of the Higgs boson in exotic particles like lepton jets in Hidden Valley models, and multi-Higgs boson cascade predicted by many models beyond the SM will be also illustrated.
        Speaker: Stefano Giagu (Sapienza University of Rome)
        Slides
      • 10:20
        Charged Higgs probes of dark bosons 15m
        We suggest top quark decays as a venue to search for light dark force carriers. The top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 sigma deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t -> b W + Z's. This is the same as the dominant top quark decay (t -> b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. We discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.
        Speaker: Kyoungchul Kong (University of Kansas)
        Slides
    • 10:40 11:10
      Break 30m Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

    • 11:10 12:30
      LHC Probes of Dark Sectors I Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Convener: stephane willocq (University of Massachusetts)
      • 11:10
        Dark Matter searches at ATLAS 15m
        Numerous independent astrophysical experiments have observed and measured the influence of the phenomenon named Dark Matter, but its nature is still unknown. If the assumption that Dark Matter is a particle which has a weak coupling to the Standard Model is valid, then collider searches have the ability to search for the production of this new Weakly Interacting Massive Particle (WIMP). Any Dark Matter particles produced in collisions would escape the detector without being observed. Signatures which include an initial-state radiated particle balancing a large amount of Missing Transverse Momentum, known as mono-X topologies, provide a generic means of conducting Dark Matter searches. ATLAS has conducted several mono-X searches, including recoiling jets, photons, W/Z bosons which decay hadronically, and Z bosons which decay leptonically. Searches were carried out with centre of mass energies of both 7 and 8 TeV, and with up to 20/fb of data. No evidence for physics beyond the Standard Model is observed, and thus limits are placed on both Effective Field Theory models and Simplified Models of Dark Matter. These constraints are converted into bounds on WIMP-nucleon cross sections and WIMP annihilation cross-sections.
        Speaker: Steven Schramm (University of Toronto)
        Slides
      • 11:30
        Dark Matter Searches at CMS 15m
        Speaker: Jordan Damgov (Texas Tech University)
        Slides
      • 11:50
        Searches for Hidden Valleys at ATLAS 15m
        Hidden Valley models contain a hidden sector that communicates with the Standard Model via a scalar. The hidden sector phenomenology is unconstrained. It can be as complex or simple as desired, and prompt or long lived. In this case we explore the ATLAS program to search for long lived versions of the Hidden Valley model. The benchmark model is fairly simple, produces two hidden valley pions that decay somewhere in the detector. Many theories may generate these signatures. ATLAS has three custom triggers designed to capture these events, which are described, as well as an analysis designed to look for the very long decay length items. Sensitivity after the upgrade will also be addressed.
        Speaker: Gordon Watts (University of Washington)
        Slides
      • 12:10
        Searches for Hidden Valleys at CMS 15m
        Speaker: John Paul Chou (Rutgers University)
        Slides
    • 12:30 14:00
      Lunch 1h 30m Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

    • 14:00 15:30
      LHC Probes of Dark Sectors II Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Convener: John Paul Chou (Rutgers University)
      • 14:00
        SUSY Dark Matter searches at CMS 15m
        In this talk I will discuss Implications of CMS Run 1 SUSY searches for the SUSY neutralino as a WIMP Dark Matter candidate
        Speaker: Fedor Ratnikov (Inst. für Exp. Kernphysik)
        Slides
      • 14:20
        SUSY Dark Matter searches at ATLAS 15m
        Supersymmetry provides an excellent dark matter candidate. SUSY searches at ATLAS are sensitive to an extensive range of scenarios with either a neutralino or a gravitino as the lightest supersymmetric particle. In this talk I will present the latest results from analyses carried out using the Run 1 dataset collected by ATLAS at the LHC at 8 TeV center of mass energy.
        Speaker: Estel Perez Codina (TRIUMF)
        Slides
      • 14:40
        Search for exotic particles at LHCb 15m
        LHCb, located on the LHC, is a fully instrumented forward detector with flexible triggers, low pileup, and excellent secondary vertex resolution which make it an ideal experiment to search for unique exotic signals. A review of current LHCb exotic particle searches is given. Searches for the anomalous decays of B-mesons and tau-leptons are presented, as well as direct searches through central exclusive production, di-tau production, bbbar asymmetry, and displaced secondary vertices.
        Speaker: James Philip Ilten (Massachusetts Institute of Technology)
        Slides
      • 15:00
        Dark Photon Searches at ALICE 15m
        ALICE is one of the largest experiments at the Large Hadron Collider at CERN and is designed to study the physics of strongly interacting matter at extreme high temperature and energy densities created in high-energy heavy ion collisions. ALICE has a good potential to search for a dark photon signal in pi0 and eta Dalitz decays, thanks to the excellent resolution of the tracking system and the high statistics of di-electrons pairs from Dalitz decays. The upgrade of the major ALICE detectors is foreseen to take place during the 2018 Long Shutdown (LS2). In this way, the experiment will fully exploit the high-luminosity Pb-Pb collisions provided by the LHC, recording events at a 50kHz rate. These conditions will significantly increase the dark photon search capabilities of ALICE. In this presentation, the current status of dark photon searches in the Run1 data sample will be shown and the expected constraints for the dark photon mixing parameter in the Run-2 and Run-3 conditions will be discussed.
        Speaker: Taku Gunji (Center for Nuclear Study, the University of Tokyo)
        Slides
      • 15:20
        Discussion 10m
    • 15:30 16:00
      Break 30m Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

    • 16:00 17:30
      Dark Matter and Dark Interactions Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Convener: Tobias Golling (Yale University)
      • 16:00
        Dark Matter Direct Detections 25m
        Speaker: Kathryn Zurek (University of Michigan)
        Slides
      • 16:30
        Dark matter annihilations in the Galactic Center 25m
        Past studies have identified a spatially extended excess of ~1-3 GeV gamma rays from the region surrounding the Galactic Center, consistent with the emission expected from annihilating dark matter. Recent improvements in the analysis techniques have found this excess to be robust and highly statistically significant, with a spectrum, angular distribution, and overall normalization that is in good agreement with that predicted by simple annihilating dark matter models. For example, the signal is very well fit by a 31-40 GeV dark matter particle annihilating to b quarks with an annihilation cross section of sigma v = (1.7-2.3) x 10^-26 cm^3/s. Furthermore, the angular distribution of the excess is approximately spherically symmetric and centered around the dynamical center of the Milky Way (within ~0.05 degrees of Sgr A*), showing no sign of elongation along or perpendicular to the Galactic Plane. The signal is observed to extend to at least 10 degrees from the Galactic Center, disfavoring the possibility that this emission originates from millisecond pulsars.
        Speaker: Dan Hooper (Fermilab)
        Slides
      • 17:00
        CMB Constraints on Dark Matter Annihilation 15m
        The Cosmic Microwave Background (CMB) is a remarkably powerful and clean probe of dark matter annihilation. I will review the constraints from existing CMB and low-redshift data, and discuss future prospects from current and upcoming CMB experiments such as Planck and Advanced ACTpol. Many simple models designed to explain various indirect detection anomalies can be decisively tested with the CMB in the next few years.
        Speaker: Neelima Sehgal (Stony Brook University)
        Slides
      • 17:20
        Discussion 10m
    • 18:30 21:30
      Workshop Dinner 3h The Fifth Season 34 E. Broadway Port Jefferson, NY

      The Fifth Season 34 E. Broadway Port Jefferson, NY

      The Fifth Season
      34 E. Broadway
      Port Jefferson, NY

    • 09:00 10:30
      Axions and Axion-like particles Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Convener: Dr Hong Ma (BNL)
      • 09:00
        Black hole portal into hidden valleys 25m
        I will discuss electromagnetic signals of black hole superradiance in the presence of an axion coupled to a hidden QCD-like sector.
        Speaker: Sergei Dubovsky (New York University)
        Slides
      • 09:30
        ADMX 20m
        The axion is a well-motivated cold dark matter candidate first postulated to explain the absence of CP violation in strong interactions. Dark matter axions may be detected via their resonant conversion into photons in a high-Q microwave cavity permeated by a strong magnetic field. The Axion Dark Matter eXperiment (ADMX) has used this technique to exclude axion models in the few μeV mass range. Much of axion dark matter parameter space has until recently been beyond the reach of experiment, but advances in amplifier technology have enabled quantum-limited axion detection around 20 μeV (5 GHz); ADMX-HF (high-frequency), currently under construction at Yale University, will have sufficient sensitivity to probe this region of parameter space. This talk will cover the principles of the microwave cavity axion search and the status of current experiments, with a focus on ADMX-HF. I will also discuss R&D efforts by the ADMX-HF collaboration aimed at extending the microwave cavity technique to weaker couplings and higher frequencies.
        Speaker: Benjamin Brubaker (Yale University)
        Slides
      • 09:55
        Cosmic Axion Spin Precession Experiment (CASPEr) 20m
        We propose an experiment to search for QCD axion and axion-like-particle (ALP) dark matter. Nuclei that are interacting with the background axion dark matter acquire time-varying CP-odd nuclear moments such as an electric dipole moment. In analogy with nuclear magnetic resonance, these moments cause precession of nuclear spins in a material sample in the presence of a background electric field. This precession can be detected through high-precision magnetometry. With current techniques, this experiment has sensitivity to axion masses m_a <~ 10^(-9) eV, corresponding to theoretically well-motivated axion decay constants f_a >~ 10^16 GeV. With improved magnetometry, this experiment could ultimately cover the entire range of masses m_a <~ 10^(-6) eV, just beyond the region accessible to current axion searches.
        Speaker: Surjeet Rajendran (Stanford)
        Slides
      • 10:20
        Discussion 10m
    • 10:30 11:00
      Break 30m Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

    • 11:00 12:30
      Cosmology and astrophysics Physics Department, Bldg. 510, Large Seminar Room

      Physics Department, Bldg. 510, Large Seminar Room

      Brookhaven National Laboratory

      Convener: Dr Mary Bishai (Brookhaven National Laboratory)
      • 11:00
        Neutrinos and hidden physics (sterile neutrinos) 25m
        The existence of sterile neutrinos has been presented as an explanation for many anomalous results in experimental astro-particle physics. This talk will discuss existing experimental indications for eV-scale sterile neutrinos, while surveying future prospects for resolving these hints at accelerator, reactor, and radioactive source neutrino experiments.
        Speaker: Bryce Littlejohn (University Of Cincinnati)
        Slides
      • 11:30
        Cosmology probes of dark sectors 25m
        Speaker: Kendrik Smith (Perimeter Institute)
        Slides
      • 12:00
        Concluding remarks and outlook 25m
        Speaker: Maxim Pospelov (University of Victoria)