1. July 2001 Neil Spooner WIMP LIMITS Update on WIMP Direct and Indirect Searches Neil Spooner, University of Sheffield Direct Results Towards 1 Ton and why Indirect Results Xenon Directional

2. July 2001 Neil Spooner Science Case Update All viable cosmological scenarios involve CDMAll viable cosmological scenarios involve CDM Halo sizes are larger - typically 200 kpc in spiralsHalo sizes are larger - typically 200 kpc in spirals Cosmology case never so strong as now excluded probably excluded by accelerators theoretically plausible mass region 1 10 100 1000 10 0.1 0.001 WIMP mass (proton masses) events per kg per day Particle Physics Consensus(?) that “natural”Consensus(?) that “natural” SUSY models have minimum  p ~10 -10 pb (SI) Some recent calculations by Ellis, Ferstl, Olive show lower expectations

3. July 2001 Neil Spooner WIMP DIRECT DETECTION WIMP MDMD MTMT Expected featureless differential nuclear recoil energy spectrum for stationary detector ---> looks like electron background Kinematics Kinematics dR dE R = RoRo EorEor e -E R /E o r recoil energy incident energy kinematic factor = 4M D M T /(M D + M T ) 2 event rate per unit mass total event rate (point like nucleus) 123456789100 (E o r/R o )*dR(v E,v esc )/dE R E/(E 0 r) 0 1 2 3 4 5 6 7 8 9 10 Observed spectrum Observed spectrum dR dE =R o S(E) F 2 (E) I(A) obs (1) Nuclear recoil discrimination (2) Directional signal

4. July 2001 Neil Spooner WIMP Modulation 6 60 0 ~30 kms -1 ~220 kms -1 Sun Earth Jun 2nd WIMP Directional - diurnal (E o r/R o )dR/dE Annual modulation E/(E o r) SMALL BIG

5. July 2001 Neil Spooner Many Experiments USC-PNL-Zaragoza Neuchatel-Caltech-PSI UCSB-UCB-LBL HDMS (Heidelberg-Moscow) GENIUS (Heidelberg) TANDAR-USC-PNL-Zaragoza GEDEON (MOZA collaboration) UKDMC (IC-Sheffield-RAL) NAIAD (UKDMC) DAMA (Rome) ELEGANTS SACLAY USC-PNL-Zaragoza ANAIS (Zaragoza) DAMA (Rome) ELEGANTS VI (Osaka, Otho) CASPAR (Sheffield) DAMA (Rome) MACHe3 ZEPLIN I (UKDMC) ZEPLIN II (UK-UCLA-Torino) DRIFT (UK-UCSD-Oxy-Temple) SIMPLE (Paris VII-Lisbon) PICASO SIMPLE CRESST-I (MPI-TUM-Oxford) CUORCINO(Italy-US collab) CUORE (Italy-US collab) ROSEBUD (IAS-IAP-Zaragoza) PASS (UBC-Bayreuth) ORPHEUS(Bern) SALOPARD(Lisbon-Paris-Zaragoza) CDMS-I (US collaboration) CDMS-II (US collaboration) EDELWEISS-I (French collab) EDELWEISS-II (French collab) CRESST-II (MPI-TUM-Oxford) Recent progress in WIMP dark matter detection reviewed by speakers at workshop on the Identification of Dark Matter (IDM2000) held in York, UK (18-22 September). 94 talks on Dark Matter Ionisation Thermal Scintillation Dual Techniques Superheated Droplets Directional

6. July 2001 Neil Spooner RESULTS - Spin Dependent Limits on WIMP-proton cross-section. DAMA limits, PLB 1996; UKDMC limits, PRL 1996; CRESST, 2001; EDELWEISS, 1996 From CRESST

7. July 2001 Neil Spooner RESULTS - Spin Independent Limits on WIMP-nucleon cross-section. DAMA positive signal, PLB 2000; DAMA limits, PLB 1996; CDMS at Stanford, PRL 2000; CRESST, 2001; EDELWEISS, 2001

8. July 2001 Neil Spooner IONISATION DETECTORS Ge (natural / enriched) ionisation detectors used by several collaborations. Detectors of high radiopurity and ultra-low visible energy threshold. Quenching factor ~ 25%. Ge isotopes moderately heavy (A~73) and reasonably sensitive to spin- dependent interactions. However…electron recoil background rejection impossible using this technique alone (although Compton veto possible).

9. July 2001 Neil Spooner IGEX 3 x 2kg high-purity enriched Ge (86% 76 Ge) detectors mounted in Canfranc tunnel (Spanish Pyrenees). Special attention paid to shielding of external gamma and neutron radiation.

10. July 2001 Neil Spooner COSME Ge in Canfranc Underground Laboratory No discrimination 72.7 kgxdays IGEX-DM - (PLB 2000) Previous result new result

11. July 2001 Neil Spooner HDMS Heidelberg Dark Matter Search (HDMS) use different approach. Active Ge shield surrounded by high purity Pb and Cu. Compton background events in inner detector vetoed by outer. Prototype Parameters

12. July 2001 Neil Spooner HDMS Results Current limits for 9.9 kg  days New set up with Inner detector from enriched 73 Ge, use of ultra high purity copper etc. Experiment was installed at Gran Sasso in August 2000. projected sensitivity but no discrimination, no identification of a signal possible. IGEX, COSME…...

13. July 2001 Neil Spooner SCINTILLATION DETECTORS Established technique. Well-suited to large target masses (search for annual modulation). Detectors of high radiopurity (although not as pure as Ge). Often contain heavy nuclei (I, Xe) and nuclei sensitive to spin-dependent interactions (Na, F). Quenching factor often low (e.g. ~ 9% for I in NaI) and visible energy threshold higher than for bolometers => relatively high recoil energy threshold. BUT…..electron recoil background rejection possible using scintillation Pulse-Shape Discrimination (PSD).

14. July 2001 Neil Spooner DAMA - NaI Annual Modulation New NaI 3/4 -38475 kg.days. Total 4 years annual modulation - 57986 kg.days Annual modulation few% of signal Residuals from 2-6 keV INFN/AE-00/01 No recoil discrimination

15. July 2001 Neil Spooner DAMA Region Our estimated PSD limit that would be obtainable by DAMA DAMA/NaI-0 - 4123.2 kg  days - pulse-shape analysis, limits; DAMA/NaI1-4 - 57986 kg  days - annual modulation, signal; Predictions for PSA for the whole data set (DAMA/NaI0-4): improvement of limit by a factor of √[(57986+4123.2)/4123.2]=3.9 UKDM+Saclay paper, sub Astro-p

16. July 2001 Neil Spooner UKDMC NAIAD - Pulse Shape Dis. low activity silica light guides & PMT shield double zone refined NaI(Tl) crystal PMT Example time constant distributions for new crystal DM72 showing log gauss neutron and compton fits and data.  E - 12-15 keV neutron Compton 1996 limit from DM46 spin-independent Schematic of early NaI detector e.g. DM46 NaI(Tl) Integrated Pulse- Shape

17. July 2001 Neil Spooner Following improvement in DM46 (5 kg) - discovery of fast events in NaI Data (  E 35-40 keV) calibration Example  histogram for DM46 showing anomalous events Typical fast event energy distributions in various crystals of different geometry Many tests performed on different crystals/configurations NaI Anomalous Events (1998) Anomaly

18. July 2001 Neil Spooner UKDMC NaI + Saclay very similar spectrum of fast events seen again RESULT this despite very different manufacture and geometry Collaboration with Saclay to run a “DAMA” crystal at Boulby anomalous event spectra in NaI Saclay (“DAMA”) spectrum UKDMC spectrum

19. July 2001 Neil Spooner UKDMC spectrum Saclay (“DAMA”) spectrum DM74 limit on fast event spectrum UKDMC spectrum Saclay (“DAMA”) spectrum DM74 limit on fast event spectrum anomalous event spectra in NaI anomalous events reduced in NaI RESULT BUT at least 3-4 months exposure to Rn would be needed! - difficult to explain Confirmed with unencapsulated NaI (DM74)  distribution for pre-polished unencapsulated crystal DM74 after 5 mns operation no fast events within stat Identification of the events Are the fast events in any way related to the DAMA result?

20. July 2001 Neil Spooner DAMA PSD UKDMC anomalous event spectra Limit on anomalous events from DAMA old PSD data

21. July 2001 Neil Spooner NAIAD - unencapsulated array 40-50 kg Unencapsulated surface controlled NaI 10 kg Saclay crystal NaI unencapsulated crane glove box OFHC box PTFE crystal cage

22. July 2001 Neil Spooner NAIAD Preliminary Results ELEGANT CaF 2,ELEGANT V, Canfranc… (annual modulation and inelastic scattering used)

23. July 2001 Neil Spooner ELEGANT CaF 2 CaF 2 (Eu) target with undoped CaF 2 light-guide. Oto-Cosmo site (1500 mwe) Contains 3.7 kg of 19 F (good for spin- dependent couplings). Integral CsI(Tl) veto shield. Veto events in light-guide with pulse- height ratio in each PMT. Beam tests show 19 F quenching factor increases with decreased energy => improved recoil energy threshold. CaF 2 (Eu) CaF 2

24. July 2001 Neil Spooner ELEGANT V Large mass (730 kg) NaI(Tl) Plastic scintillator veto. Energy threshold 4-5 keV ee. Background ~ 10 /keV/kg/day at threshold (too high!). Lower threshold system being designed (cooled PMTs / PD readout?). look for gammas emitted by low-level nuclear states excited by WIMP-nucleus inelastic scattering + recoil energy line is close to 210 Pb X-ray so large background subtraction needed (1) annual modulation (2) inelastic scattering

25. July 2001 Neil Spooner CRYOGENIC BOLOMETERS Detect small temperature rise in solid caused by recoil energy deposit. Have advantage that almost any crystalline material can be used => possible target nuclei with high mass / spin-dependent coupling. Detectors of high radiopurity and ultra-low visible energy threshold. Quenching factor ~ 100% as most energy released as heat. CRESST I, ROSEBUD, ELEGANT LiF, Milan TeO 2 …... No background rejection with this technique alone.

26. July 2001 Neil Spooner CRESST I Uses W superconducting transition-edge thermometers to measure temperature rise in 4 x 262g Al 2 O 3 crystals (small change in T gives large change in resistivity). Operates at 12 mK. Superb energy resolution, even at low energy (133 eV @ 1.5 keV):

27. July 2001 Neil Spooner ROSEBUD Installed at Canfranc laboratory. 50g Al 2 O 3 and 67g Ge crystals with NTD Ge thermistor temperature sensors. Again, superb energy resolution at low energy typical of cryogenic bolometers:

28. July 2001 Neil Spooner ELEGANT LiF Uses F nuclei giving optimum sensitivity to spin-dependent interactions. 8 x 21 g LiF crystals with thermistor read-out. Reject microphonic / pick- up noise events using c 2 and peak-height/peak-area cuts: Pick-up Microphonics

29. July 2001 Neil Spooner Milan TeO 2 Currently 20 x 334g TeO2 crystals (6.7 kg total) read-out by NTD thermistor. Intend to scale-up to > 56 x 750g crystals (CUORICINO). R&D for CUORICINO already indicates best a spectrometer ever produced (4 keV FWHM @ 5.4 MeV):

30. July 2001 Neil Spooner COMBINED DETECTORS Discrimination between nuclear recoil signal events and electron recoil background possible by measuring relative pulse-heights in several different read-out channels of combined detectors. Retain benefits of individual techniques (low threshold, low background etc.) Very powerful technique used by many new experiments. Possibilities include: –Ionisation / thermal (Ge or Si cryogenic bolometers). –Scintillation / thermal (cryogenic scintillator crystals). –Ionisation / scintillation (double-phase Xe detectors).

31. July 2001 Neil Spooner CDMS I (Ion/Therm) 1998 - 1.6 kg.days Si ZIP (4 recoil events observed) 1999-2000 - 10.6 kg.days Ge BLIP (17 nuclear recoil events observed) Present experiment - Ge and Si ionisation + thermal at Stanford Site See a total of 13 recoil candidates events > 10 keV event rate is in region of DAMA signal electrons

32. July 2001 Neil Spooner CDMS vs. DAMA CDMS - expected spectra for DAMA region DAMA/1-4 (3s) ~2.3 event/kgGe/day Observed CDMS Nuclear Recoils DAMA/1-4 (3  ) Lowest cross-section (40 GeV, 2.3 10 -42 cm 2 ) DAMA/1-4 (3  ) Most Likely Fit (52 GeV, 7.2 10 -42 cm 2 )

33. July 2001 Neil Spooner CDMS limit 13 single NRs similar to that expected for DAMA BUT strong evidence that these events are caused by neutrons --> 4 multiple scatter recoils observed in Ge in same data DAMA and CDMS experiments are incompatible at 99.76% CL Although problem with neutrons due to shallow site New analysis, new run at Sanford Move to Soudan CDMS 90% limits on WIMP- nucleon cross-section. CDMS sensitivity because the number of multiple scatters observed is larger than expected, the limit is lower than the median simulated sensitivity Conclusion

34. July 2001 Neil Spooner EDELWEISS (Ion./Therm) 3 x 320g Ge detectors with NTD thermistor read-out. Observe four distinct populations of events from neutron source calibrations => imperfect charge collection from surface recoils. Similar effects seen by CDMS.

35. July 2001 Neil Spooner EDELWEISS (Ion/Therm) 320 g Ge detector Heat and ionisation 5.03 kg  days of exposure Dashed vertical line - energy threshold

36. July 2001 Neil Spooner EDELWEISS New limit

37. July 2001 Neil Spooner EDELWEISS II - Predictions aim for 500 kg.days Ge - use 50 cm borated poly expected rate 5 x 10 -4 events/kg/keV/day in 8-40 kev after background rejection predictions prediction

38. July 2001 Neil Spooner CRESST-II (Scint./Therm) CRESST propose use of CaWO 4 cryogenic scintillator crystals. Detect light with existing Al 2 O 3 thermal absorber technology. Tests show 99.7% discrimination at 15 keV recoil energy threshold! Propose 10 kg detector with 1 /keV/kg/day background.

39. July 2001 Neil Spooner CRESST II - Predictions CRESST, phase II  WIMP -nucleon [pb] Predictions for CRESST Phase II 30 kg  years of CaWO 4 99.7% background rejection above 15 keV CRESST II prediction

40. July 2001 Neil Spooner To reach 10 -10 pbMotivation Ionisation - Germanium: GENIUS proposal for 100kg --> 1 ton ?Possibilities Scintillation - NaI: LIBRA (DAMA) 250 kg under construction Intrinsic low background but NO discrimination and expensive (mainly  ) Ionisation/thermal - CDMS - Cryo-array ?: Annual modulation (what if DAMA region ruled out), PSD not sensitive enough Good discrimination but difficult technology and expensive XENON - ZEPLIN-MAX proposal for 1 ton - BDMC (UKDMC, US, Europe) Good discrimination, world expertise, simpler technology(?), less expensive TOWARDS 1 TON? Community needs to grow up ---> much larger collaborationsImplications Detector needs recoil discrimination at scaleable cost

41. July 2001 Neil Spooner XENON High-A target (Xe~130) for WIMP masses 50-500 GeV/c 2 to reach 0.01/kg/d, and ultimately 0.0001 kg/d Motivation for a big Xe programme --> Complements NaI low-A, q(A) > 0.2 --> satisfies basic requirement for: (i) recoil identification (ii) diagnostic array capability Powerful discrimination (typically x100 better than NaI) with different techniques and geometry possible Big scale-up potential (yet retains recoil identification) Lower cost than alternatives? (low temperature, Ge..) --> experience of ICARUS, UCLA, Suzuki, Aprile, Prospects for isotopic enrichment better than Ge…... ICARUS-UCLA ITEP Doke group (Japan) DAMA World expertise UKDMC Columbia

42. July 2001 Neil Spooner Xe * +Xe Xe 2 * Triplet 27ns Singlet 3ns 2Xe 175nm Excitation (recombination) Xe ** + Xe Xe 2 + +e - Xe + +Xe Ionisation Nuclear/Electron Recoil three discrimination techniques (1) scintillation pulse shape (2) ionisation-scintillation - low field- (3) ionisation-scintillation - high field, low threshold - single phase Xe two phase Xe liquid gas XENON (PSD and Scint/Ion)

43. July 2001 Neil Spooner 1 Ton Xe - ZEPLIN-MAX ZEPLIN-I single phase PSD 4 kg ZEPLIN-II ion-scint two phase Xe 30 kg ZEPLIN-III Ion-scint two phase Xe high field 6 kg ZEPLIN array under construction existing ZEPLIN-MAX ion-scint two phase Xe 1000 kg MULTINATIONAL concept Larged staged programme towards 1 ton by the BDMC UCLA, Columbia UK DMC: Sheffield, ICSTM, RAL European: US: Growing collaboration ZEPLIN I,II,III ITEP, CERN/Padova,Torino, Coimbra, Boulby Dark Matter Collaboration (BDMC) UKDMC

44. July 2001 Neil Spooner Pb shielding Top of ZEPLIN I veto Boulby stub 2 laboratory xenon purification XENON - ZEPLIN I,I,III (UKDMC et al) ZEPLIN I underground BOULBY stub 2 lab

45. July 2001 Neil Spooner ZEPLIN II (UKDMC collaboration with US and Italy) Completion due end 2001 cooling rings PTFE cone OFHC copper plate shielding, integration, readout, daq UKDMC ~30kg Lxe detector UCLA, Torino, Padova ionisation-scintillation discrimination

46. July 2001 Neil Spooner ZEPLIN III ionisation-scintillation - low threshold 6 kg liquid Xe High field (20 kV) operation for better discrimination 31 two-inch photomultipliers Xe Completion due end 2001 (UKDMC collaboration with US and Russia)

47. July 2001 Neil Spooner ZEPLIN - 1 ton Concept ZEPLIN-MAX A BDMC multinational programme Final design by mid 2002 Recoil Discrimination Construction 2004+ Options being explored: (I) single unit, (II) 4 units, (III) modular (IV) mass + low threshold units RESULT: (a) attain 0.0001/kg/d, (b) diagnostic array with complementary techniques 3 modules 80 kg target 4 sub- units shielding One possibility

48. July 2001 Neil Spooner ZEPLIN-XENON Predictions NaI 1996 limit ZEPLIN 2002/3 ZEPLIN I/II 2003 ZEPLIN II/III 2004 10 -3 10 -4 10 -5 10 -6 10 -7 10 -8 10 -9 10 -10 101001000 WIMP-nucleon cross-section, pb WIMP mass GeV CDMS II CRESST II ZEPLIN-MAX 2006 ZEPLIN predictions based on prototype tests and operation of ZEPLIN I Other Xe: DAMA, KAMIOKA (also plan 1 ton Xe)

49. July 2001 Neil Spooner XENON - DAMA Operating 6.5 kg Kr free ( 85 Kr beta emitter) Liquid Xenon with PSD. 99.5% enriched in 129 Xe (spin-dependent couplings). Viewed by three MgF 2 PMTs through quartz windows (l=175 nm). Measured quenching factor ~ 45% - 65%. Stable operation at -105 o C. (see Nuovo Cim 19 (1996) 537)

50. July 2001 Neil Spooner XENON - Kamioka (Scint/Ion) Liquid-gas double phase xenon 0.3l low background construction 8 cm drift to proportional scintillation region 99% background rejection for 10-100 keV 3 months continuous operation 1 kg experiment in Kamioka Also considering 1 Ton Xe

51. July 2001 Neil Spooner GENIUS - 1 Ton Ge? GENIUS - Ge proposal by H-M collaboration Heidelberg group propose to build on their experience with HDMS => GENIUS. Mount unencapsulated enriched HPGe detectors directly in LN 2 dewar. Shield workshop during zone- refining / assembly to minimise cosmics. Expect ultra-low background. ‘HEP-scale’ project !

52. July 2001 Neil Spooner GENINO GENIUS - 100 Kg --> Ton Ge? no recoil discrimination = no signal predictions

53. July 2001 Neil Spooner DIRECTIONAL Q: What else can we do to identify a WIMP signal? We can be more clever: S(A,E R ) is in fact also function of recoil direction due to earth’s motion through DM halo. =>A: We can be more clever: S(A,E R ) is in fact also function of recoil direction due to earth’s motion through DM halo. => Search for diurnal modulation to signal in directional detector. 6 60 0 ~30 kms -1 ~220 kms -1 Sun Earth Jun. 2nd WIMP S(A,E R ) => S(A,E R,  ) ~ exp(-((v E cos  - v min )/v 0 ) 2 ) D.N. Spergel, Phys. Rev. D 37 (1988) 1353

54. July 2001 Neil Spooner DRIFT Project MWPC Occidental Temple SS vacuum vessel with internal Cu shielding, access flanges and silica calibration windows vessel UKDMC The DRIFT-1 detector 1.1 m Multi-Wire Proportional Counter Readout field cage Gas and data UKDMC (UKDMC collaboration with US) A BDMC multinational programme

55. July 2001 Neil Spooner DRIFT Concept Negative Ion Drift An old idea revisited by J. Martoff E.W McDaniels et al., RSI 28 (1957) 864 H.R. Crane et al., RSI 32 (1961) 953 E CS 2 - ions drift Xe WIMP anode MWPC readout cathode Longitudinal and transverse diffusion of ions is much less than for electrons --> typically < 1mm per m No need for magnet Readout by conventional MWPC Use CS 2 + Ar, Xe at 10-80 Torr Electrons from ionised tracks reversibly attach to CS 2 and drift to anode gammas recoil discrimination C recoils S recoils gammas recoil discrimination gammas alphas S recoil region (>90%) alpha discrimination 1 foot cube detector @6keV: 99.9% gamma rejection, 95% alpha rejection (from wires) (UKDMC collaboration with US - Oxy, Temple, LLNL)

56. July 2001 Neil Spooner DRIFT-1 Integration at Sheffield The first ever direction sensitive dark matter detector A BDMC multinational programme

57. July 2001 Neil Spooner DRIFT 1 site Installation Aug 01 DRIFT 1 - Installation Aug 01 Part of 1500 m 2 new facility at Boulby - 3000 mwe depth

58. July 2001 Neil Spooner DRIFT-1 Predicted limits Full background audit for DRIFT-1 completed (tests and MCs) a background of ~ 5 counts per year per m 3 is feasible DRIFT-1 can yield a limit below DAMA CONCLUSION DRIFT-1 could just detect a directional signal at 10 -5 pb

59. July 2001 Neil Spooner DRIFT-10, towards 1 ton a BDMC - multinational programme --> need 1 ton to get enough counts at minimum SUSY DRIFT-1 DRIFT-10 1 ton CS 2 Xe DRIFT-MAX - 1 Ton gas?

60. July 2001 Neil Spooner Other Techniques - Droplets The peculiar requirements of direct search dark matter experiments also lend themselves to the use of many other novel techniques……. Superheated liquid droplets sealed in gel matrix. Nuclear recoil causes liquid to boil creating bubble. LET of electron recoils insufficient to trigger bubble formation. Widely used in nuclear industry for neutron dosimetry. Superheated Droplet Detectors SIMPLE PICASO Detect bubble formation via piezo-electric transucers

61. July 2001 Neil Spooner SDD - Results SIMPLE: 0.19 kg  days - blue curve (limit) 25 kg  days - red curve (projected sensitivity) PICASO: CCl 2 F 2, C 3 F 8, C 4 F 10, C 2 ClF 5 1.34 g of freon 117 days of data taking

62. July 2001 Neil Spooner Other Techniques - 3 He - MACHe3 Use 3 He cell => recoil energy converted to quasi- particles which damp vibrating wires. Hole allows diffusion of excitations. Tag neutrons with inelastic excitation. Low Compton cross-section => low background rate. Ultra-low recoil energy threshold. Propose matrix of 1000 cells of 125 cm 3 each! Abstract 622, F. Mayet

63. July 2001 Neil Spooner Summary Direct Limits Current sensitivity ≈ 10 -6 pb –DAMA: NaI annual modulation of rate –UKDMC: NaI ‘anomalous’ events seen also Saclay –CDMS: needs neutron subtraction –EDELWEISS: new result http://cdms.berkeley.edu/limitplots/ - - - - - New high mass, high discriminaiton detectors needed XENON? EDELWEISS CDMS DAMA

64. July 2001 Neil Spooner INDIRECT DETECTION Annihilation in Halo, Earth, Sun or Galactic Centre  WW,ZZ, ,gg,...  e ,p, ,,.. Halo: positron, antiproton, gamma secondary decay products, mono-energetic gamma lines Earth, Sun, Galactic centre: High energy neutrinos SignatureExperiment Halo annihilation Positron, Antiproton Gamma rays  Z   BESS, CAPRICE, AMS,.. GLAST, VERITAS, MILAGRO,…. Earth, Sun, GC Neutrino SuperK, Baksan,IMB, MACRO AMANDA, ANTARES, Baikal, … High degree of complementarity between direct and indirect searches E.g. high m  => low direct detection rate but substantial annhilation rate

65. July 2001 Neil Spooner Indirect Searches - Results Bergstrom, Edsjo, Gondolo 1998 annihilations in Sun, Earth, GC: e.g. SuperK, AMANDA, ANTARES...  Advantages: keeps original directions, like gammas Use muons (best range in ice/water) - bkgd is atmos so look down Flux too low from halo unless DM clumped, Sun best (H easier to calculate) - less model dependent though problem is Earth-Sun perturbations on  Some correlation between neutralino-proton cross-section and muon flux but Example models SUN Thresholds > 10 GeV => heavy neutralinos Neutralino mass determination possible via  angular distribution still demonstartes complementarity of direct and indirect searches - small cross section could still give high rate

66. July 2001 Neil Spooner Indirect Searches - Results Muons from Sun and Earth: SuperK, AMANDA B10, MACRO, Baksan DAMA ann. mod  si Possible contradiction with DAMA? Earth Earth muon predictions - Bergstrom et al., Phys. Rev. D (1998) SuperK00 limits DF Cowan SUN MACRO99 Bergstrom, Edsjo, Gondolo 1998 SuperK00 Astro-ph/0007003 Astro-ph/9905021 IDM2000

67. July 2001 Neil Spooner Indirect Searches - Results Muons from Sun, Erath and Galactic Centre: Super-Kamiokande From Super-K contribution to ICRC2001 Super-K limit CDMS limit 3  allowed region from DAMA Combined Sun, Earth and GC, from opposite plot, using Kamionkowski et al. (1995) conservative neutrino spectra to convert from muon flux limit to WIMP-nucleon cross section

68. July 2001 Neil Spooner Indirect Searches - Future Future sensitivity: estimated comparison of CRESST, UKDMC, ANTARES Predicted sensitivity of underwater/under-ice neutrino telescopes to spin-dependent WIMP-proton interactions in comparison with direct WIMP searches. 0.1 km 2 x 3 yrs CRESS T UKDM-Xe ANTARES

69. July 2001 Neil Spooner Indirect Searches - Halo BESS CAPRICE Antiproton flux at top of atmosphere: e.g. CAPRICE98, BESS balloon In principle sensitive to neutralinos (high mass) but predictions difficult Signal is featureless and depends on Solar wind/galactic propagation models Background, from CRs on the ISM, also featureless including sub-100 MeV Difficult to distinguish pure CR background from CR + neutralino Annihilation upper and lower limit predictions for secondary antiprotons by Simon et al. (1998). (i.e. Background) secondary antiproton flux predictions by Bergstrom and Ullio From CRs (1999). Primary antiproton flux from 964 GeV neutralino annihilations in the halo. Ullio Astro-PH/9904086 Example comparison with specific model Positron detection also suffers from lack of a clear signature Positron fraction from HEAT Best fit to excess 380 GeV neutralinos

70. July 2001 Neil Spooner AMS01 on the Space Shuttle Indirect Searches - Halo Antiproton, positrons and photons from annihilations: AMS  9 days in space in 1998 AMS02 on Space Station Launch due in Oct 2003

71. July 2001 Neil Spooner Indirect Searches - Halo Gammas in the halo: e.g. ACTs and Space-borne - GLAST, VERITAS…. Bergstrom, Buckley, Ullio 1998 Example predictions   ZZ  Advtg: directional information (like, unlike antiproton) and lines Most likely e.g. E  = m  But rates difficult to predict (SUSY param, halo profile) Recent MSSM calculations: (i) ATCs (large areas) potential at highest predicted rates, (ii) GLAST (high resolution) potential <250 GeV Needs cusp!

72. July 2001 Neil Spooner Summary DAMA NaI annual modulation as objective WIMP or fluctuating low energy noise? UKDMC NaI ‘anomalous events’ Seen in Saclay (DAMA) crystal! CDMS recoil limit (almost) excludes DAMA Subtraction of neutron signal Several detectors becoming sensitive at 10 -6 pb Need 1 ton with high recoil discrimination to get enough counts …XENON very promising Indirect searches reaching sensitivities to exclude models