outline Dark Matter Search with Antimatter Current status and - PowerPoint PPT Presentation

TA U P 2 0 1 9 S e p 1 0 t h 2 0 1 9 THE GRAMS PROJECT DUAL MEV GAMMA-RAY AND DARK MATTER OBSERVATORY T S U G U O A R A M A K I , S L AC

outline Dark Matter Search with Antimatter Current status and recent results of indirect dark matter search Why is antimatter survey important? Antimatter-based dark matter search with GRAMS MeV Gamma-Ray Observations Current status of MeV gamma-ray observations Why are MeV gamma-ray observations important? MeV gamma-ray observations with GRAMS Summary GRAMS First Paper accepted in Astroparticle Physics Aramaki et al., 2019

Dark Matter Search

INDIRECT Dark Matter SEARCH � 4 MEASURE DM ANNIHILATION/DECAY PRODUCTS DM q, h, W, _ _ _ e + , γ , ν , p, d, n… DM a POSITRON: ANTIPROTON: AMS-02, PAMELA, DAMPE… AMS-02, PAMELA, BESS, GAPS , GRAMS GAMMA RAY: ANTIDEUTERON: FERMI-LAT, VERITAS, CTA, GRAMS … AMS-02, BESS, GAPS , GRAMS NEUTRINO: ANTIHELIUM: ICECUBE, ANTARES… AMS-02, GAPS , GRAMS COMPLEMENTARY SEARCHES WITH DIFFERENT DETECTION METHODS AND BACKGROUND MODELS ARE CRUCIAL TO VALIDATE DM SIGNATURES

<latexit sha1_base64="mn4t03Afz1AIdBXox69qkMUN1ZQ=">AB8XicbVDLSsNAFL3xWeur6tLNYCm4KokIdlw47KCfWAbymR60w6dTMLMRCihf+HGhSJu/Rt3/o2TNgtPTBwOGcu9wTJIJr47rfzsbm1vbObmvH9weHRcOTnt6DhVDNsFrHqBVSj4BLbhuBvUQhjQKB3WB6m/vdJ1Sax/LBzBL0IzqWPOSMGis9DgKqsmBOgvKwUnXr7gJknXgFqUKB1rDyNRjFLI1QGiao1n3PTYyfUWU4EzgvD1KNCWVTOsa+pZJGqP1skXhOalYZkTBW9klDFurviYxGWs8im6wWUTPRq14u/uf1UxM2/IzLJDUo2XJRmApiYpKfT0ZcITNiZglitushE2oszYkvISvNWT10nqu5Zfn9dbTaKOkpwDhdwCR7cQBPuoAVtYCDhGV7hzdHOi/PufCy/bjFzBn8gfP5A8wCkEs=</latexit> <latexit sha1_base64="mn4t03Afz1AIdBXox69qkMUN1ZQ=">AB8XicbVDLSsNAFL3xWeur6tLNYCm4KokIdlw47KCfWAbymR60w6dTMLMRCihf+HGhSJu/Rt3/o2TNgtPTBwOGcu9wTJIJr47rfzsbm1vbObmvH9weHRcOTnt6DhVDNsFrHqBVSj4BLbhuBvUQhjQKB3WB6m/vdJ1Sax/LBzBL0IzqWPOSMGis9DgKqsmBOgvKwUnXr7gJknXgFqUKB1rDyNRjFLI1QGiao1n3PTYyfUWU4EzgvD1KNCWVTOsa+pZJGqP1skXhOalYZkTBW9klDFurviYxGWs8im6wWUTPRq14u/uf1UxM2/IzLJDUo2XJRmApiYpKfT0ZcITNiZglitushE2oszYkvISvNWT10nqu5Zfn9dbTaKOkpwDhdwCR7cQBPuoAVtYCDhGV7hzdHOi/PufCy/bjFzBn8gfP5A8wCkEs=</latexit> <latexit sha1_base64="mn4t03Afz1AIdBXox69qkMUN1ZQ=">AB8XicbVDLSsNAFL3xWeur6tLNYCm4KokIdlw47KCfWAbymR60w6dTMLMRCihf+HGhSJu/Rt3/o2TNgtPTBwOGcu9wTJIJr47rfzsbm1vbObmvH9weHRcOTnt6DhVDNsFrHqBVSj4BLbhuBvUQhjQKB3WB6m/vdJ1Sax/LBzBL0IzqWPOSMGis9DgKqsmBOgvKwUnXr7gJknXgFqUKB1rDyNRjFLI1QGiao1n3PTYyfUWU4EzgvD1KNCWVTOsa+pZJGqP1skXhOalYZkTBW9klDFurviYxGWs8im6wWUTPRq14u/uf1UxM2/IzLJDUo2XJRmApiYpKfT0ZcITNiZglitushE2oszYkvISvNWT10nqu5Zfn9dbTaKOkpwDhdwCR7cQBPuoAVtYCDhGV7hzdHOi/PufCy/bjFzBn8gfP5A8wCkEs=</latexit> <latexit sha1_base64="mn4t03Afz1AIdBXox69qkMUN1ZQ=">AB8XicbVDLSsNAFL3xWeur6tLNYCm4KokIdlw47KCfWAbymR60w6dTMLMRCihf+HGhSJu/Rt3/o2TNgtPTBwOGcu9wTJIJr47rfzsbm1vbObmvH9weHRcOTnt6DhVDNsFrHqBVSj4BLbhuBvUQhjQKB3WB6m/vdJ1Sax/LBzBL0IzqWPOSMGis9DgKqsmBOgvKwUnXr7gJknXgFqUKB1rDyNRjFLI1QGiao1n3PTYyfUWU4EzgvD1KNCWVTOsa+pZJGqP1skXhOalYZkTBW9klDFurviYxGWs8im6wWUTPRq14u/uf1UxM2/IzLJDUo2XJRmApiYpKfT0ZcITNiZglitushE2oszYkvISvNWT10nqu5Zfn9dbTaKOkpwDhdwCR7cQBPuoAVtYCDhGV7hzdHOi/PufCy/bjFzBn8gfP5A8wCkEs=</latexit> Recent Results from fermi-lat � 5 Launched in June 2008, targeting 20MeV - 300GeV gamma-rays Possible DM signatures from Galactic Center Region (GCE) Inconsistent with dwarf spheroidal galaxy (dSph) observations (recent observations for new dSphs show some small excess) 10 -24 Daylan et al., 2016 — Fermi Dwarf Galaxy Observation (Ackermann et al., 2015) 10 -25 Excluded < σ v > [cm 3 /s] Thermal Relic Cross Section gamma-ray excess observed (Steigman et al., 2012) 10 -26 Fermi Galactic Center Excess — Calore et al., 2014 — Daylan et al., 2014 Propagation model: MED FERMI GALACTIC CENTER EXCESS (GCE) ¯ — Abazajian et al., 2015 bb ~50GeV DM or astrophysical objects ? 10 -27 10 100 1000 m ᵪ [GeV] DIFFICULT TO VERIFY DM SIGNATURES DUE TO MIMIC SIGNAL FROM BACKGROUND NEED A NEW APPROACH/EXPERIMENT TO VALIDATE THE RESULTS

Recent Results from ams-02 � 6 Launched in May 2011, targeting cosmic-rays including antiparticles Possible DM detection in antiproton measurements Possible detection of antiheliums and antideutrons 10 1 2 Flux (GeV m -2 s -1 sr -1 ) bkg dm 10 0 AMS-02 ~50GeV DM? 10 -1 10 -2 10 -3 E k Cui et al. 2016) 10 -4 _ _ 10 -1 10 0 10 1 10 2 10 3 So far, 6 3 He, 2 4 He candidate events reported E k (GeV) ▶ Antiproton excess: ~50GeV DM ( consistent with Fermi GCE ) or cosmic-ray interaction ? PLANCK ▶ Antiheluim detection: ▶ If from DM, a large excess should be seen in the antiproton/antideuteron fluxes? ▶ antimatter clouds in our galaxy? NEED A NEW APPROACH, EXPERIMENT TO VALIDATE THE RESULTS

WHY ANTIDEUTERONS? � 7 BACKGROUND-FREE DM SEARCH AT LOW-ENERGY 10 -3 Antideuteron Flux [m- 2 s -1 sr -1 (GeV/n) -1 ] PRIMARY FLUX BESS upper limit — DM, m ᵪ = 30GeV DM ANNIHILATION/DECAY 10 -4 — background GAPS AMS-02 AMS-02 _ 
 _ 
 DM d p 10 -5 q,h,W… DM _ 
 n GRAMS 10 -6 Aramaki et al., 2016 DARK MATTER 
 HADRONIZATION COALESCENCE 
 ANNIHILATION PROCESS PROCESS (P C ) ~ 400x 10 -7 10 -8 SECONDARY FLUX LSP: Donato et al., 2008 COSMIC RAY INTERACTION _ 
 BKG: Ibarra et al., 2013 d 10 -9 _ _ 0.1 1 10 100 p (CR) +H (ISM) → p + H + p + n + p + n Kinetic Energy per Nucleon [GeV/n] GAPS FIRST SCIENCE FLIGHT IS SCHEDULED FROM ANTARCTIC IN 2021 GRAMS: NEXT GENERATION EXPERIMENT

GRAMS Antimatter Detection Concept � 8 MEASURE ATOMIC X-RAYS AND ANNIHILATION PRODUCTS _ d π - TOF Plastic Scintillator ATOMIC TRANSITIONS Auger e - EXOTIC ATOM _ n o ,l o Refilling e - d n=n K ~40 X-ray π + p Ar y X - r a π + X-RAY X-ray LAr TPC X-RAY π - X-RAY π - n=2 ⎛ ⎞ * 1 2 − 1 2 M A time of flight (TOF) system tags 
 E γ = zZ ( ) * R ⎜ ⎟ ⎜ ⎟ H candidate events and records velocity 2 m n f n i π + n=1 ⎝ ⎠ π 0 e The antiparticle slows down & stops, p π - NUCLEAR forming an excited exotic atom ANNIHILATION π - π + De-excitation X-rays provide signature Aramaki et al., 2013 Concept proven with accelerator beam test Annihilation products provide additional 
 Cascade model developed for X-ray yields background suppression

GRAMS antideuteron identification technique � 9 CR p, e ± REJECTION: ANTIPROTON AND ANTIDEUTERON SELECTION Select slow particles with TOF Simultaneous detection of secondary/ annihilation products (pions/protons) ▸ Slow CR p and e ± may not be able to produce secondary particles ANTIDEUTERON IDENTIFICATION FROM ANTIPROTONS Atomic X-rays from exotic atom ▶ different energy: 58, 97 keV for antiproton, 74, 114 keV for antideuterons Pion/proton multiplicity ▶ antideuterons produce more pions and protons Stopping range (depth sensing) ▶ antideuterons with the same velocity go deeper before stopping dE/dX energy deposit in LArTPC PLANCK ▶ antideuterons with the same velocity deposit more energy EXPECTED BACKGROUND/MIMIC EVENTS ~0.01

GRAMS Detector Design � 10 LARTPC DETECTOR SURROUNDED BY PLASTIC SCINTILLATORS LARTPC MEASURES SCINTILLATION LIGHT AND IONIZATION ELECTRONS Anode wires/pads _ Segmentation π - d (X-Y plane) Plastic Scintillator E-FIELD Scintillation Light Ionization Electrons X-ray π + - r a y X p π + X - LAr TPC r a y 1.4m x 1.4m x 20cm LArTPC π - SiPMs π - Plastic Scintillators : TOF - measure velocity and incoming angle LArTPC : Calorimeter and particle tracker ▶ Scintillation light at SiPMs to trigger events ▶ Wires/pads on anode plane (X, Y), drift time (Z) to provide a 3D image/track ▶ Well-studied, widely-used in large-scale DM/neutrino experiments Scintillation light localized by segmentation to reduce coincident background