DUSEL NATIONAL LAB ROLE ESSENTIAL FOR SNOLAB AND DUSEL EXPERIMENTS SLUO

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1 Search for Dark Matter WIMPs: SuperCDMS Soudan Soudan and SNOLAB leading to GEODM at DUSEL NATIONAL LAB ROLE ESSENTIAL FOR SNOLAB AND DUSEL EXPERIMENTS SLUO - September 17, 2009 Blas Cabrera - Stanford University and KIPAC Spokesperson for SuperCDMS Fermilab, SLAC and 12 Universities in collaboration - more needed Outline: State of the Direct Detection of Dark Matter field - CDMS-II in Soudan leads the field - SuperCDMS Soudan 15 kg approved - SLAC starts - SuperCDMS SNOLAB 150 kg base design - SLAC major - GEODM at DUSEL 1,500 kg concept design - SLAC lead 1

2 Standard Model of Cosmology A surprising but consistent picture Ω matter Not ordinary matter (Baryons) Ω m >> Ω b = ± from Nucleosynthesis WMAP χ? + internally to WMAP Ω m h2 Ω b h 2 15 σ's Mostly cold: Not light neutrinos small scale structure 2

3 CDMS Complementarity LHC, direct and indirect Halo made of WIMPs 1/2 shown for clarity WIMP scattering on Earth: e.g. CDMS : currently leading the field WIMP production on Earth WIMP annihilation in the cosmos GLAST/Fermi Launched 11 June

4 Complementarity msugra/cmssm Direct Detection: sensitive to Bulk and Focus point regions LHC sensitive to low energy or low mass region Indirect Detection e.g. Fermi/GLAST sensitive to Focus and Higgs funnel regions CDMS II Current Bulk σ SI [cm 2 ] CDMS II Final Soudan Focus Point Higgs Funnel 100 pb -1 1 fb SNOLAB Coannihilation LHC DUSEL χ 1 Mass [GeV/c ] 4

5 Direct Detection: semiconductors and noble liquids CDMS No events seen, <1 expected Need more than one technique for convincing detection Xenon10 10 events seen, 7 expected WARP (LAr) Large background leaking into signal region 5

6 SUF (17 mwe), Soudan (2090 mwe), & SNOLAB (6060 mwe) At SUF 17 mwe 0.5 n/d/kg At Soudan 2090 mwe 10 4 less muons At SNOLAB 6060 mwe 10 7 less muons At DUSEL 7000 mwe Log 10 (Muon Flux) (m -2 s -1 ) Depth (meters water equivalent) 6

7 Advanced Soudan detectors CDMS-II ZIPs: 3 dia x 1 cm => 0.25 kg of Ge Existing ZIPs SuperCDMS ZIPs: 3 dia x 1 => 0.64 kg of Ge ZIPs for SuperCDMS 7

8 Design demonstrated for SNOLAB and DUSEL New design has been demonstrated with interleaved charge and phonon symmetrically on both sides. It provides at least two orders of magnitude improved rejection which meets ton-scale specifications. SuperCDMS Soudan detectors - each 0.6 kg 1 x 3 dia SuperCDMS SNOLAB detectors - each 1.5 kg 1.3 x 4 dia 8

9 Summary For past five years CDMS-II has and continues to lead direct detection field papers submitted on axion search and on low mass WIMPs final analysis near completion (~x3) Zero background strategy very successful and vital for maintaining discovery potential SuperCDMS Soudan 15 kg improves sensitivity by another factor of x4 beyond CDMS-II Probing central supersymmetry region Complementary to LHC and indirect detection Advanced double-sided interleaved design looks very promising for future Ge 150 kg and 1,500 kg (SLAC role essential for these experiments) 9

10 Backup Slides 10

11 Fundamental basis for better rejection ~10% ~1% 100% 11

12 Continue zero background strategy Tower 1-5 XENON10 12

13 Successful zero background operation Background rejection key to successful high discovery potential Achieved using large S/N from phonon and ionization signals Ratio of charge to phonon (yield) and the phonon timing information Expected Background: 0.6 ± 0.5 surface events and < 0.2 neutrons 10 kev energy calibration 0 Observed Events 13

14 Relationship of GEODM to SuperCDMS Best case DUSEL 4800 in 2015 and 7400 in 2017 All direct detection experiments need intermediate phase Ge 100 kg at SNOLAB enables future 1.5 ton at DUSEL Engineering for future GEODM at DUSEL S4 NSF funded R&D for large detectors σ SI [cm 2 ] CDMS II Current CDMS II Final 2 1 Soudan SNOLAB 3 4 # need DOE partnership for these experiments DUSEL χ 1 Mass [GeV/c ] #!"#$%&'(!)*'+!,-)*./0*1,2'(*!34$0"5$67##D;*#6:K*0%!=6#1B;*(:'*#.1#2;&2#);.B;#;&1# 14