Possibilities for MeV-GeV DM at accelerators Gordan Krnjaic, Nhan - PowerPoint PPT Presentation

Possibilities for MeV-GeV DM at accelerators Gordan Krnjaic, Nhan Tran, Andrew Whitbeck [Fermilab]

P REFACE AND OUTLINE Not going to go into the physics and motivation in much detail Just some quick overview of the various possibilities New: a muon beam fixed target experiment at FNAL Then ponder we can discuss how this could evolve towards 2026 and beyond 2

A CCELERATORS FOR LIGHT DM 83 84 Direct Detection Targets 10 - 35. all the direct detection bounds 10 - 37. (current and future) Elastic Scalar Accelerator Targets Thermal Relic Targets & Current Constraints 10 - 39. 10 - 4. 10 - 41. 10 - 6. y = e 2 a D H m c ê m A' L 4 10 - 43. 10 - 8. Majorana Fermion s e H cm 2 L Elastic & Inelastic Scalar Relic Targets Elastic & Inelastic Scalar Relic Targets 10 - 45. 10 - 10. Pseudo - Dirac Fermion Relic Target Pseudo - Dirac Fermion Relic Target Majorana Relic Target Majorana Relic Target 10 - 47. 10 - 12. 10 - 49. Inelastic Scalar 10 - 14. 10 - 51. 10 - 16. H Pseudo L Dirac Fermion 10 2 10 3 1 10 10 - 53. m c @ MeV D 10 - 55. 1 10 10 2 10 3 m DM H MeV L 85 86 Accelerators provide strong complementarity to DD over a range of 87 thermal targets because it can produce DM candidates relativistically 3

LDMX Missing mass / momentum / energy Beam dump All Beam Dump Experiments ( Kinetic Mixing ) Missing Mass / Momentum Experiments ( Kinetic Mixing ) LHC 10 - 4 10 - 4 10 - 5 10 - 5 LEP 10 - 6 10 - 6 DarkLight E787 / 949 @ BNL @ JLab MiniBooNE 10 - 7 10 - 7 y = � 2 � D ( m � / m A' ) 4 y = � 2 � D ( m � / m A' ) 4 PADME @ LNF BaBar 10 - 8 10 - 8 BDX 10 - 9 10 - 9 MMAPS 10 - 10 10 - 10 @ Cornell NA64 VEPP - 3 E137 Belle II @ CERN @ BINP 10 - 11 10 - 11 Scalar Relic Target Scalar Relic Target LSND Majorana Relic Target Majorana Relic Target 10 - 12 10 - 12 Pseudo - Dirac Relic Target Pseudo - Dirac Relic Target 10 - 13 10 - 13 10 - 14 10 - 14 10 - 15 10 - 15 LDMX @ SLAC 10 - 16 10 - 16 10 2 10 3 10 2 10 3 1 10 1 10 m � [ MeV ] m � [ MeV ] LDMX Will come back to proton beam dumps 4

LDMX- μ GK, Yoni Kahn (Princeton), NT, AW, arXiv: 1803.XXXXX https://indico.fnal.gov/event/16719 1) Model independent test of g-2 anomaly 2) Probe models of muon-philic dark matter 5

1m L DM X Dipole Magnet 6 HCAL target ECAL tagging 
 recoil 
 tracker tracker Hcal: Fe/Scintillator sampling calo high sampling fraction is good for high efficiency neutron detection Synergy with CMS HCal calorimeter Ecal is based on CMS HGCal readout electronics (QIE) Si calorimeter has high radiation tolerance and good MIP tracking

LDMX- μ main difference 20 cm Magnet ECal tagging tracker 50 X 0 HCal Target recoil tracker σ (p)/p ~ % Strip tracker (D0, HPS) CMS HL-LHC ECal Endcap Fe-Scintillator HCal (CMS electronics) 7

LDMX- μ and FNAL Targets Seaquest ~1e13 PoT Phase 1: MTest “Shovel ready” 10 10 Muons on target, 50 X 0 target ~100 days with 10 5 muons per spill Phase 2: NM4, Seaquest Zoom in: M-Test 10 13 Muons on target, 50 X 0 target 3 years with 10 7 muons per spill detector hall #1 detector hall #2 proton beam π ,e, μ μ 120 GeV target block of iron (12ft.) 8

See talk by R.G. Van de Water at PAC DM @ SBND https://indico.fnal.gov/event/15726/session/3/material/0/0.pdf More Protons with a Dedicated Dump: OpFon 2 with 6.0E20 POT Direct Detec0on 10 - 6 Lower Limits 10 - 7 g-2 anomaly 10 - 8 • SBND with improved MiniBooNE beam dump will probe 10 - 9 scalar relic density line. Y = ϵ 2 α ' ( m χ / m V ) 4 • π 0 (high mass) and electron (low mass) 10 - 10 channels complement each other. 10 - 11 • Including beam 0ming SBND Inelastic π 0 Relic Density will improve DM search MiniBooNE SBND NCE Electron 10 - 12 for masses > 50 MeV. Direct Detection LSND E137 BaBar K + →π + + invisible m V = 3m χ 10 - 13 α D = 0.5 Electron / Muon g - 2 J / ψ→ invisible 10 - 2 10 - 1 1 21 m χ ( GeV ) 9

T OWARDS 2026 10

T OWARDS 2026 LDMX-e is working towards long white paper (early summer) funding for or finding a beam line + funding for a detector = challenge Possibilities: DASEL (SLAC), CEBAF (JLAB), SPS (CERN) Timelines are vague/fluid — there is a phase-1 and phase-2 LDMX- μ pheno paper out soon Need to find time at FTBF , but beam line exists Only need a few months Could be engineering run for LDMX-e detector Proton beam dumps remain an option Complementary to LDMX-e/ μ in mass and couplings 11