WIMP: direct and indirect detection Results and perspectives

Transcription

1 WIMP: direct and indirect detection Results and perspectives G. Gerbier CEA/Saclay, DAPNIA LSM (Fréjus Lab) - Introduction for -not so- pedestrians - Summary of direct detection exp status : few focus on some exp. issues / news - What «indirect» detection brings in the game : complementarity - Perspectives G Gerbier NOON 2004 Tokyo- Feb 14th 1

2 Cosmological constraints after WMAP Ω tot = 1.00 ± 0.02 Ω baryon = ± Ω matter 0.3 Ω Λ 0.7 Ω ν < 0.01 ο Σ mν < 1-2 ev Need for «invisible» matter at all scales G Gerbier NOON 2004 Tokyo- Feb 14th 2

3 At local galactic scale - can it be non luminous stars? No G Gerbier NOON 2004 Tokyo- Feb 14th 3

4 A galactic halo of dark matter -SUSY provides a large class of «MSSM» (5 free parameters) with Ω χ ~ 0.3 => -Axion also good candidate : not subject of this talk -«Rotation curve» provides the local density -«direct»detection by «table top» expts -«Indirect» detection of annililation products G Gerbier NOON 2004 Tokyo- Feb 14th 4

5 Wimp direct detection experiments (underground sites mandatory) CDMS (Soudan) ZEPLIN-II -III XENON CryoArray MAJORANA ZEPLIN, NaIAD, DRIFT (Boulby) IGEX ROSEBUD ANAIS (Canfranc) EDELWEISS (Fréjus) CRESST, HDMS/GENIUS DAMA/LIBRA CUORICINO/CUORE (Gran Sasso) KIMS (YY) ELEGANTS, LiF XMASS (SK) G Gerbier NOON 2004 Tokyo- Feb 14th 5

6 WIMP identification, signatures Nuclear (NOT electron) recoil at kev energies Annual modulation of event rate: Maxwell velocity distribution of WIMPs in non-rotating halo superimposed with rotation of galaxy and motion of Earth around the sun modulation of WIMP flux max. 7% expected Will soon require > 1 ton target Directionality of recoil nucleus: diurnal modulation of recoil direction due to Earth s rotation record track of recoil nucleus in low pressure gas target G Gerbier NOON 2004 Tokyo- Feb 14th 6

7 Ge WIMP direct detection schemes with and w/o background rejection Liquid Xe Ionization Scintillation NaI, CaF 2, LXe, stat PSA Ge, Si WIMP target Phonons WIMP CaWO4, BGO, Al 2 O 3, LiF, Elastic scattering off nuclei Drukier and Stodolsky 1984 Goodman, Witten 1985 G Gerbier NOON 2004 Tokyo- Feb 14th 7

8 Detector strategies: experiments with and without background rejection No nuclear recoil discrimination CUORICINO/CUORE CRESST-I HDMS IGEX NaIAD, ANAIS DAMA/LIBRA + ann mod ZEPLIN I to III KIMS EDELWEISS-I and -II CDMS-I and -II CRESST-II ROSEBUD DRIFT SIMPLE/PICASSO MACHe3/ORPHEUS 42 kg 760 kg Te02 1kg Al2O3 0.2 kg Ge in 2.5 kg Ge 2 kg Ge Nuclear recoil discrimination : statistical, evt/evt kg NaI kg NaI 4 kg liq Xe, up to 1 ton CsI (Tl), 80 kg in , 10 to 35 kg Ge 1, 10 kg Ge and Si 10 kg CaWO kg BGO (CaWO4, ) Directional, discriminating but digital, and other experiments CS2 directional Freon areogels, digital Few grams He3, to 1kg Gran Sasso Gran Sasso Gran Sasso Canfranc Boulby/Canfranc Gran Sasso Boulby Yang Yang (700 m) Fréjus Lab (LSM) Stanford, Soudan mine Gran Sasso Canfranc Boulby Rustrel, SNOLAB Grenoble/Bern G Gerbier NOON 2004 Tokyo- Feb 14th 8

9 CEA-Saclay DAPNIA and DRECAM CRTBT Grenoble CSNSM Orsay IAP Paris IPN Lyon FZ-Karlsruhe and Univ. Karlsruhez + JINR Dubna in LSM or Fréjus lab 4800 mwe - µ flux = 4/m 2 /d - neutron flux = /s/cm 2 G Gerbier NOON 2004 Tokyo- Feb 14th 9

10 1kg stage of EDELWEISS I : 3 * 320 g Ge. Cu screens without Roman Pb lateral shield 1 st data taking: Fall 2000, 1 detector mounted and used 3kg.d 2 nd data taking : Spring 2002, 1 detector used out of kg.d 3 rd data taking : October March 2003, 3 detect kg.d 4 th data taking : April -Nov 2003, 3 detectors - 30 kg.d Archeological lead 3 * 320 g Ge detectors May 2002 GGA1,GeAl9,GeAl10 October 2002 GGA3, GSA1, GSA3 320 g detector G Gerbier NOON 2004 Tokyo- Feb 14th 10

11 Bolometer-1: Q = f(e r ) diagram - «Noisy» episode? -Events in red (1 inside and 3 outside the neutron zone) all arriving within an interval of a few days out of 90 days total acq time What about spilling of these events with 10 times more exposure? 20 kev NB : 100 % efficiency at true nuclear recoil energy threshold G Gerbier NOON 2004 Tokyo- Feb 14th 11

12 EDELWEISS results with 3 rd data set- Correct for : Efficiencies : nucl. rec, fraction of Wimp signal kept Trigger eff. =100 % > threshold No background subtraction Same conventional halo, nucl. phys. parameters for both experiments Excludes DAMA candidate at 99.8% C.L. Excludes DAMA best fit at % C.L. Copi and Krauss : (Phys.Rev. D67 (2003) ) exclusion is model independent 4th data set (30 kg.d) takenwithlowthreshold-10 kev - analysis in progress paper by summer 2004 G Gerbier NOON 2004 Tokyo- Feb 14th 12

13 Nov 2003 HE run - : Identification of alphas by their anomalous quenching factor -fewα /kg.d 210 Po worry : are 210 Pb and 210 Bi β emitters also present?? -surface events have bad charge collection so have lower Q than expected and pollute signal zone - surface cleaning/radon reduction (see Cuoricino) G Gerbier NOON 2004 Tokyo- Feb 14th 13

14 Future = Edelweiss-II phase -March 2004: end EDELWEISS-I -Install EDELWEISS-II with 28 x 320 g Ge = 9 kg -100 detector capacity Large volume -50l- cryostat -Thicker 50 cm PE shield Dilution : 8-10 mk OK + µ Veto Wiring and cold electronic test : summer 2003 G Gerbier NOON 2004 Tokyo- Feb 14th 14

15 DAMA : TAUP 2003 nov 2003 G Gerbier NOON 2004 Tokyo- Feb 14th 15

16 DAMA 100 kg NaI Signature = annual modulation TAUP 2003 L. Bergstrom DAMA 3σ allowed region 1997 DAMA 1996 exclusion limit from PSD kg.d See coming talk by P. Belli G Gerbier NOON 2004 Tokyo- Feb 14th 16

17 CDMS Cryogenic Dark Matter Search - 11 US labs Ge BLIP detectors NTD thermistors SUF 17 mwe depth Neutrons limit the sensitivity Ge + 2 Si ZIP detectors at shallow site SUF 17 mwe depth Similar results 2003 and beyond 12 ZIP detectors at deep site Soudan Mine 2090 mwe depth First dark ~ months taken 18 more detectors in fab (4 kg Ge total) New! Recoil Energy (kev) Be patient : first results should be soon available Ionization Yield Cross section [cm 2 ] (normalised to nucleon) Gaitskell&Mandic CDMS WIMP Mass [GeV] G Gerbier NOON 2004 Tokyo- Feb 14th 17

18 CDMS detectors performance x y z localisation => identification of surface events G Gerbier NOON 2004 Tokyo- Feb 14th 18

19 CDMS II at Soudan G Gerbier NOON 2004 Tokyo- Feb 14th 19

20 CRESST II (German + UK collab) background rejection by phonon + scintillation measurement CaWO 4 scintillating absorber W thermometers Sapphire light detector 300 g detector module CRESST-II: 6 g test detector: 99.7 % rejection above 15 kev no surface effects Recent data taking at GS 33 x 300 g CaWO 4 66 SQUIDs Present cryostat + cold box G Gerbier NOON 2004 Tokyo- Feb 14th 20

21 Optional Rosebud (French/Spanish) Light and Heat bolometers Scintillating crystal under test Optical detector Ge disk Φ=25mm ~ µm thick V Heat V Light Reflecting cavity (Ag-coated Cu) 241 Am source α s 237 Np recoils 60 kev γ s Ge-NTDs X-ray source Optical fiber NIR LED λ=820 nm P de Marcillac -IAS- G Gerbier NOON 2004 Tokyo- Feb 14th 21

22 Rosebud : Al 2 O 3 and LiF scintillate A strong light emission is detected for Al2O3 (~ BGO)! A very good electron/nuclear recoil separation is achieved Very good news for ROSEBUD & CRESST! G Gerbier NOON 2004 Tokyo- Feb 14th 22

23 ZEPLIN (UK, US, Portugal collab) ZEPLIN 1 : Xe light time constants analysis Ionisation Electron/nuclear recoil Excitation Xe * Xe + Xe 2 + +Xe +e - (recombination) Xe ** + Xe +Xe 175nm Triplet 27ns Xe 2 * Singlet 3ns 175nm 2Xe 2Xe 3 kg / 1.5 pe/kev / 3 PMTs coinc. 290 kg.d G Gerbier NOON 2004 Tokyo- Feb 14th 23

24 ZEPLIN I : fighting at low energy Expected exp. distrib for 60 GeV Wimp signal with 10-6 pb evts/kg/kevee/d 0,20 0, kev (ee) 0,10 0,05 0, kev X-ray 90 kev recoil e- G Gerbier NOON 2004 Tokyo- Feb 14th 24

25 Future programme ZEPLIN I Full CH shielding Neutron measurements Low Kr Xenon ML analysis More data ZEPLIN II/III Two-phase light-charge discrimination 7 kg det deployment in 2004 ZEPLIN-MAX (IV) 1 tonne target G Gerbier NOON 2004 Tokyo- Feb 14th 25

26 XENON (US project) Provide z measurement and recoil identification : promising at kev? G Gerbier NOON 2004 Tokyo- Feb 14th 26

27 G Gerbier NOON 2004 Tokyo- Feb 14th 27

28 XMASS : 100kg Xe detector + next step 800 kg 54 2-inch low BG PMTs Liq. Xe (30cm) 3 = 30L= 100Kg Low background setup Vertex, energy reconstruction self-shielding purification system Menu of R&D with 100kg detector MgF 2 window Vertex/energy: based on scintillation light pattern. e/gamma separation attenuation length neutron BG study Xe recoil/e PSD Dark matter search G Gerbier NOON 2004 Tokyo- Feb 14th 28

29 Experimental status and theoretical predictions EDELWEISS-I present EDELWEISS-II, CDMS-II ZEPLIN-III sensitivity goals 1 Ton sensitivity goal (optimistic) L. Rozkowski et al., hep-ph/ G Gerbier NOON 2004 Tokyo- Feb 14th 29

30 How to test most of SUSY parameter space NB : picobarn = 5 evts/ton/y Gamma-ray background: Extreme background rejection Neutron background: (Very) deep site mandatory Efficient muon veto (fast neutrons) Detection of multiple scattering interactions Requires > 1000 detectors in very compact design or fine position resolution G Gerbier NOON 2004 Tokyo- Feb 14th 30

31 Identification of residual neutron interactions (U/Th ) Identification by multiple scattering interactions Requires > 1000 detectors (edge effects) + compact design CUORICINO starting CUORE: 760 kg at 10 mk > 95 % neutron identification efficiency possible CUORICINO tower G Gerbier NOON 2004 Tokyo- Feb 14th 31

32 χ ν χ WIMP annihilation - ν from the Center of Earth or Sun - γ ray from halo (line) or from galactic center - p,e + from galactic halo χ + χ b + b C + µ + ν µ χ + χ q + q π 0 γγ p, e+ χ + χ γ (Ζ) + γ «Smoking gun» G Gerbier NOON 2004 Tokyo- Feb 14th 32

33 Wimps indirect detection experiments Satellites: GLAST, PAMELA, AMS-02 BAKSAN, BAIKAL VERITAS MAGIC ANTARES NESTOR SUPER K BESS HESS CANGAROO AMANDA, ICECUBE G Gerbier NOON 2004 Tokyo- Feb 14th 33

34 Illustration : muons coming from earth or sun - NB : need a model for halo and annililation of WIMPs to compare with direct detection : standard halo + MSSM = interplay between direct and indirect =>SK/ANTARES are more efficient than EDW for rejecting some MSSM models dominated by SD coupling (Sun is proton rich) G Gerbier NOON 2004 Tokyo- Feb 14th 34

35 G Gerbier NOON 2004 Tokyo- Feb 14th 35

36 G Gerbier NOON 2004 Tokyo- Feb 14th 36

37 Conclusions Dark Matter needed Cold Dark Matter favoured Neutrinos and MACHO s are small fraction of it SUSY χ «best» candidate Direct detection WIMP experiments (EDELWEISS, CDMS, and soon ZEPLIN) sensitive to optimistic- SUSY models ( 10-6 pbarn) DAMA candidate still seen Next generation experiments (in 10 to 100 kg scale) might allow factor improvement in sensitivity (10-8 pbarn), and begin to test more realistic models Testing the bulk of SUSY parameter space (down to pbarn) will require experiments in the one-ton range and extreme background rejection Indirect detection is complementary (spin-dependent couplings for v s), but hardly competitive for low σ scalar interactions models Together with LHC, direct and indirect detection experiments should allow to pinpoint WIMP DM An axion signal could change the game G Gerbier NOON 2004 Tokyo- Feb 14th 37

38 Illustration of nuclear recoil identification Ionisation-heat (phonon) detectors WIMP (~ 200 km/s) X interacts γ by elastic diffusion on nuclei Electron recoil =>Nuclear recoil <E>1 100 kev =>Exponential distribution =>Low WIMP, rate neutron evt/kg/d Nuclear recoil Electrode Al Thermic sensor (NTD Ge) Monocrystal Ge Guard Center Voltage amplifier V = 1-6 Volts d = 20 mm T = 20 mk Signal T = E o / C T C T = γt + A T 3 Charge amplifier Heat signal Ec Ec Charge signal guard Electrodes Al (charge collection ) Thermal bath Charge signal center Ei G Gerbier NOON 2004 Tokyo- Feb 14th 38 Ei

39 ZEPLIN I Discrimination Gamma source kev 32 ns Time constants vary with energy No reliable calibration of ratio with neutrons below 40 kev recoil pulse time constant (ns) ns Neutron source kev pulse time constant ns G Gerbier NOON 2004 Tokyo- Feb 14th 39