Direct Dark Matter Searches Marc Schumann Physik Institut, Universität Zürich What is ? Invisibles12, GGI Florence, June 27th 2012 marc.schumann@physik.uzh.ch www.physik.uzh.ch/groups/groupbaudis/xenon/
Dark Matter: (indirect) Evidence Particle Dark Matter Candidates: – WIMP → „WIMP miracle“ – Axion – SuperWIMPs – sterile neutrinos – WIMPless dark matter – Gravitino NASA/WMAP – ...
Direct WIMP Search Elastic Scattering of Target Atom WIMPs off target nuclei M. Schumann (U Zürich) – Direct Dark Matter Searches 3
Direct WIMP Search Elastic Scattering of WIMPs off target nuclei WIMP v ~ 230 km/s Fig: Jon Lomberg v ~ 230 km/s M. Schumann (U Zürich) – Direct Dark Matter Searches 4
Direct WIMP Search Elastic Scattering of WIMPs off target nuclei WIMP v ~ 230 km/s M. Schumann (U Zürich) – Direct Dark Matter Searches 5
Direct WIMP Search WIMP Elastic Scattering of WIMPs off target nuclei WIMP nuclear recoil Nuclear Recoil v ~ 230 km/s Detectable Signal M. Schumann (U Zürich) – Direct Dark Matter Searches 6
Direct WIMP Search WIMP Elastic Scattering of WIMPs off target nuclei WIMP nuclear recoil Nuclear Recoil v ~ 230 km/s Detectable Signal Gamma- and beta-particles (background) interact with the atomic electrons → electronic recoil M. Schumann (U Zürich) – Direct Dark Matter Searches 7
Direct WIMP Search WIMP Elastic Scattering of WIMPs off target nuclei WIMP nuclear recoil Nuclear Recoil v ~ 230 km/s E R ~ O(10 keV) Detectable Signal Recoil Energy: N number of target nuclei Event Rate: ρ χ /m χ local WIMP density <σ> velocity-averaged scatt. X-section Detector Local DM Physics Density M. Schumann (U Zürich) – Direct Dark Matter Searches 8
Dark Matter around us? How much is here? canonical value: 0.3 GeV/cm³
Dark Matter around us? How much is here? canonical value: 0.3 GeV/cm³
Dark Matter around us? How much is here? canonical value: 0.3 GeV/cm³
Direct WIMP Search WIMP Elastic Scattering of WIMPs off target nuclei WIMP nuclear recoil Nuclear Recoil v ~ 230 km/s E R ~ O(10 keV) Detectable Signal WIMP Expectations Recoil Energy: scalar -n interaction CMSSM: Trotta et al. CMSSM+LHC: Buchmueller et al. Event Rate: 1 event/kg/yr Detector Local DM Physics Density 1 event/ton/yr ρ χ ~0.3 GeV/ c² M. Schumann (U Zürich) – Direct Dark Matter Searches 12
Direct WIMP Search Argon A² Xenon Summary: Tiny Rates m = 100 GeV/c² R < 0.01 evt/kg/day 3 cm² = 4 x 10 – 4 E R < 100 keV form factor WIMP Expectations Recoil Energy: scalar -n interaction CMSSM: Trotta et al. CMSSM+LHC: Buchmueller et al. Event Rate: 1 event/kg/yr Detector Local DM Physics Density 1 event/ton/yr ρ χ ~0.3 GeV/ c² M. Schumann (U Zürich) – Direct Dark Matter Searches 13
Direct WIMP Search Argon A² Xenon Summary: Tiny Rates m = 100 GeV/c² R < 0.01 evt/kg/day 3 cm² = 4 x 10 – 4 E R < 100 keV form factor How to build a WIMP detector? WIMP Expectations scalar -n interaction ● large total mass, high A CMSSM: Trotta et al. CMSSM+LHC: ● low energy threshold Buchmueller et al. ● ultra low background 1 event/kg/yr ● good background discrimination 1 event/ton/yr M. Schumann (U Zürich) – Direct Dark Matter Searches 14
Backgrounds Experimental Sensitivity (mt) -1 without background: (mt) -1 / 2 with background: ] 1 - y 2 - m Background Sources [ x u l F environment: U, Th chains, K n o u M 8 U → 4 Th → m Pa → 4 U → 0 Th → 6 Ra → 2 Rn → 8 Po … 2 2 2 2 2 2 2 2 3 3 3 4 3 3 2 2 1 α β β α α α α 2 Th → 8 Ra → m Ac → 8 Th → 4 Ra → 0 Rn → 6 Po … 2 2 2 2 2 2 2 3 2 2 8 2 2 2 1 α β β α α α ● and decays (electronic recoil) Depth [mwe] ● alphas can pose a problem ( technology dependent) ● neutrons from ( ,n) and sf in rocks and detector parts ● neutrons from cosmic ray muons Electronic Recoils Nuclear Recoils (gamma, beta) (neutron, WIMPs) M. Schumann (U Zürich) – Direct Dark Matter Searches 15
Laboratori Nazionali del Gran Sasso (LNGS) XENON100 DarkSide XENON1T LNGS: 1.4km rock LNGS: 1.4km rock (3700 mwe) (3700 mwe) Other laboratories: Boulby (UK), LSM (F), Canfranc (E), Soudan (US), DAMA Sanford (US), SNOLab (CA), CRESST XENON100 Kamioka (JP), Jinping (CN), ...
World-wide Efforts SNOLAB Kamioka DEAP/CLEAN Homestake/SURF XMASS PICASSO LUX NEWAGE COUPP YangYang KIMS Boulby DRIFT (ZEPLIN) Soudan (NaIAD) LNGS CDMS-II LSM XENON Oto WIPP CoGeNT Canfranc EDELWEISS DAMA/Libra PICOLON DMTPC ArDM CRESST DarkSide JINPING (WArP) Panda-X CDEX South Pole DM-Ice M. Schumann (U Zürich) – Direct Dark Matter Searches 17
Direct WIMP Detection COUPP Tracking: PICASSO DRIFT, DMTPC, SIMPLE MIMAC, NEWAGE Phonons CDMS CRESST EDELWEISS ROSEBUD Charge Light XENON, ZEPLIN DAMA, KIMS CoGeNT LUX, Panda-X DM-Ice, XMASS CDEX/Texono ArDM, Darkside, DEAP/CLEAN MAX, DARWIN, LZ M. Schumann (U Zürich) – Direct Dark Matter Searches 18
Background Suppression Astropart. Phys. 35, 573 (2012) A Avoid Backgrounds Use of radiopure materials Shielding deep underground location large shield (Pb, water, poly) active veto (µ, coincidence) self shielding → fiducialization B Use knowledge about expected WIMP signal WIMPs interact only once → single scatter selection Examples require some position resolution Scintillation Pulse Shape WIMPs interact with target nuclei → nuclear recoils Charge/Light Ratio exploit different d E /d x from Charge/Phonon Ratio signal and background M. Schumann (U Zürich) – Direct Dark Matter Searches 19
2 Observables for Discrimination Ionization yield and Charge/Light ratio P R depend on d E /d x → discrimination L ER 1 0 7 , 1 3 1 3 0 2 Ionization / Phonon ER ( 2 0 1 NR 1 ) NR ER charge signal S2 light signal S1 Recoil Energy (keV) backgrounds Electronic Recoils CDMS-II Ionization 5 ), Discrimination O(10 – NR large acceptance s l o i c e R r a BUT: „surface events“ e c l u N → timing cut signal XENON100 Heat ~99.5% rejection @ 50% acceptance M. Schumann (U Zürich) – Direct Dark Matter Searches 20
WIMP Searches – Evolution l l e 1e– 40 k s t i a G . R m o Spin-Independent Cross Section @ ~60 GeV/c² 1e– 41 r f d e p d a 1 evt/ton/day d a 1e– 42 t o l P 1e– 43 1 evt/kg/year 1e– 44 1e– 45 1e– 46 1 evt/ton/year 1e– 47 1985 1990 1995 2000 2005 2010 2015 2020 Year M. Schumann (U Zürich) – Direct Dark Matter Searches 21
WIMP Searches – Evolution l l e 1e– 40 k s t i Oroville a HDMS 94 HDMS 94 G . R UKDMC Homestake m HDMS 98 o Spin-Independent Cross Section @ ~60 GeV/c² 1e– 41 IGEX r f DAMA 00 DAMA 98 d DAMA/Libra 08 e p d a 1 evt/ton/day d a 1e– 42 t o l P 1e– 43 1 evt/kg/year 1e– 44 Crystals Ge/NaI 1e– 45 1e– 46 1 evt/ton/year 1e– 47 1985 1990 1995 2000 2005 2010 2015 2020 Year M. Schumann (U Zürich) – Direct Dark Matter Searches 22
WIMP Searches – Evolution l l e 1e– 40 k s EDELWEISS 98 t i Oroville a HDMS 94 HDMS 94 G . R UKDMC Homestake m HDMS 98 o Spin-Independent Cross Section @ ~60 GeV/c² 1e– 41 IGEX r f DAMA 00 DAMA 98 d DAMA/Libra 08 e CDMS I 99 EDELWEISS 01 p d a CDMS I 02 1 evt/ton/day d a 1e– 42 EDELWEISS 03 t o l P CRESST 11 CDMS II 04 EDELWEISS 09 1e– 43 EDELWEISS 11 CDMS II 10 1 evt/kg/year 1e– 44 Crystals Ge/NaI Cryogenic Detectors 1e– 45 1e– 46 1 evt/ton/year 1e– 47 1985 1990 1995 2000 2005 2010 2015 2020 Year M. Schumann (U Zürich) – Direct Dark Matter Searches 23
WIMP Searches – Evolution l l e 1e– 40 k s EDELWEISS 98 t i Oroville a HDMS 94 HDMS 94 G . R UKDMC Homestake m HDMS 98 o Spin-Independent Cross Section @ ~60 GeV/c² 1e– 41 IGEX r f DAMA 00 DAMA 98 d DAMA/Libra 08 e CDMS I 99 EDELWEISS 01 p d a CDMS I 02 1 evt/ton/day d a WARP 1e– 42 EDELWEISS 03 t o ZEPLIN I l ZEPLIN II P CRESST 11 CDMS II 04 EDELWEISS 09 1e– 43 XENON10 EDELWEISS 11 CDMS II 10 ZEPLIN III XENON100 10 1 evt/kg/year 1e– 44 XENON100 11 Crystals Ge/NaI Cryogenic Detectors 1e– 45 Liquid Noble Gases Xe/Ar 1e– 46 1 evt/ton/year 1e– 47 1985 1990 1995 2000 2005 2010 2015 2020 Year M. Schumann (U Zürich) – Direct Dark Matter Searches 24
WIMP Searches – Evolution l l e 1e– 40 k s EDELWEISS 98 t i Oroville a HDMS 94 HDMS 94 G . R UKDMC Homestake m HDMS 98 o Spin-Independent Cross Section @ ~60 GeV/c² 1e– 41 IGEX r f DAMA 00 DAMA 98 d DAMA/Libra 08 e CDMS I 99 EDELWEISS 01 p d a CDMS I 02 1 evt/ton/day d a WARP 1e– 42 EDELWEISS 03 t o ZEPLIN I l ZEPLIN II P CRESST 11 CDMS II 04 EDELWEISS 09 1e– 43 XENON10 EDELWEISS 11 CDMS II 10 ZEPLIN III XENON100 10 1 evt/kg/year SuperCDMS Soudan 1e– 44 XENON100 11 Crystals Ge/NaI XENON100 XMASS Cryogenic Detectors 1e– 45 DarkSide-50 MiniClean Liquid Noble Gases Xe/Ar LUX some experiments are missing! 1e– 46 DEAP-3600 XENON1T 1 evt/ton/year 1e– 47 1985 1990 1995 2000 2005 2010 2015 2020 Year M. Schumann (U Zürich) – Direct Dark Matter Searches 25
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