Bernard Sadoulet Dept. of Physics /LBNL UC Berkeley UC Institute for Nuclear and Particle Astrophysics and Cosmology (INPAC) Dark Matter Searches Particle Cosmology Non baryonic dark matter (Axions) WIMPs: a generic consequence of new physics at TeV scale Direct Detection of WIMPs Noble Liquids Phonon Mediated Detectors DAMA Dark Matter searches Neutrinos 2008 30 May 08 1 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Standard Model of Cosmology A surprising but consistent picture Λ Ω NASA/WMAP Science Team 2006 Ωmatter Not ordinary matter (Baryons) Nucleosynthesis Ω >> Ω = 0.047 ± 0.006 from m b WMAP χ h2 h2 + internally to WMAP Ωm ≠ Ωb ≈15 σ's Mostly cold: Not light neutrinos≠ small scale structure mv < .17eV Large Scale structure+baryon oscillation + Lyman α Dark Matter searches Neutrinos 2008 30 May 08 2 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated Standard Model of Particle Physics 4. DAMA Fantastic success but Model is unstable Why is W and Z at ≈100 Mp? Need for new physics at that scale supersymmetry additional dimensions Flat: Cheng et al. PR 66 (2002) Warped: K.Agashe, G.Servant hep-ph/0403143 In order to prevent the proton to decay, a new quantum number => Stable particles: Neutralino Lowest Kaluza Klein excitation Dark Matter searches Neutrinos 2008 30 May 08 3 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Particle Cosmology Bringing both fields together: a remarkable concidence Particles in thermal equilibrium + decoupling when nonrelativistic Freeze out when annihilation rate ≈ expansion rate 3⋅10-27 cm3 / s α 2 ⇒ Ω h2 = ⇒ σ ≈ x v A M 2 Generic Class σ A EW Cosmology points to W&Z scale Inversely standard particle model requires new physics at this scale (e.g. supersymmetry or additional dimensions) => significant amount of dark matter Weakly Interacting Massive Particles 2 generic methods: Direct Detection= elastic scattering Indirect: Annihilation products γ ’s e.g. 2 γ ’s at E=M is the cleanest ν from sun &earth ≈ elastic scattering e + , p dependent on trapping time + Large Hadron Collider Dark Matter searches Neutrinos 2008 30 May 08 4 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Direct Detection Elastic scattering dn/dEr Expected event rates are low (<< radioactive background) Expected recoil spectrum Small energy deposition (≈ few keV) << typical in particle physics Signal = nuclear recoil (electrons too low in energy) ≠ Background = electron recoil (if no neutrons) Er Signatures • Nuclear recoil • Single scatter ≠ neutrons/gammas • Uniform in detector Linked to galaxy • Annual modulation (but need several thousand events) • Directionality (diurnal rotation in laboratory but 100 Å in solids) Dark Matter searches Neutrinos 2008 30 May 08 5 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Experimental Approaches A blooming field Direct Detection Techniques Ge, CS2, C3F8 DRIFT IGEX COUPP ZEPLIN II, III CDMS XENON ~20% of Energy Ge, Si EDELWEISS Xe, Ar, WARP Ionization Ne ArDM SIGN S c i - s n t y n g F t r e i a o e w l n E % l e n f a o o f H t o NAIAD E % n i h 0 e o 0 r 1 g n P ~ NaI, Xe, ZEPLIN I y CRESST I Ar, Ne DAMA CRESST II Al O , LiF XMASS ROSEBUD 2 3 DEAP !"#$%&'()$ Mini-CLEAN *+#$%&',-.$/ 0 At least two pieces of information in order to recognize nuclear recoil As large an amount of extract rare events from background information and a signal to (self consistency) noise ratio as possible + fiducial cuts (self shielding, bad regions) Dark Matter searches Neutrinos 2008 30 May 08 6 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated Status early 2007 4. DAMA Scalar coherent interaction ≈A2 -40 10 -41 DATA listed top to bottom on plot 10 CDMS (Soudan) 2005 Si (7 keV threshold) CRESST 2004 10.7 kg-day CaWO4 Edelweiss I final limit, 62 kg-days Ge 2000+2002+2003 limit WARP 2.3L, 96.5 kg-days 55 keV threshold CDMS Si 2005 ZEPLIN II (Jan 2007) result CDMS (Soudan) 2004 + 2005 Ge (7 keV threshold) -42 x x x Linear Collider Cosmology Benchmarks (preliminary) 10 EDELWEISS Roszkowski/Ruiz de Austri/Trotta 2007, CMSSM Markov Chain Monte Carlos (mu>0): 68% contour Roszkowski/Ruiz de Austri/Trotta 2007, CMSSM Markov Chain Monte Carlos (mu>0): 95% contour ] (normalised to nucleon) 2 x x x Ellis et. al Theory region post-LEP benchmark points Baltz and Gondolo, 2004, Markov Chain Monte Carlos CDMS Ge 2005 -43 10 Cross-section [cm -44 10 y 1 2 3 t 10 10 10 i v 2 i WIMP Mass [GeV/c ] t i s s n e Three Challenges e n se s s ns it iti g v • Understand/Calibrate detectors iv ity o l i ∝ ty • Be background free MT ∝ much more sensitive than M T sensitivity ∝ constant background subtraction eventually limited by systematics log(exposure=target mass M × time T) • Increase mass while staying background free Dark Matter searches Neutrinos 2008 30 May 08 7 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Current results 3 examples in more details Direct Detection Techniques Ge, CS2, C3F8 DRIFT Xenon 10 as generic for CDMSIGEX as generic for COUPP ZEPLIN II ,WARP, ArDM ZEPLIN II, III EDELWEISS &CDMS CRESST XENON ~20% of Energy Ge, Si EDELWEISS Xe, Ar, WARP Ionization Ne ArDM SIGN S c i - s n t y n g F t r e i a o e w l n E % l e n f a o o f H t o NAIAD E % n i h 0 e o 0 r 1 g n P ~ NaI, Xe, ZEPLIN I y CRESST I Ar, Ne DAMA CRESST II Al O , LiF XMASS ROSEBUD 2 3 DEAP !"#$%&'()$ Mini-CLEAN *+#$%&',-.$/ 0 + New ideas DAMA/Libra e.g. Monroe new modulation result Nygren Dark Matter searches Neutrinos 2008 30 May 08 8 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3.Phonon mediated 4.DAMA The Noble Liquid Revolution Noble liquids are both excellent scintillators and ionization collectors => get to large mass while maintaining excellent background by self shielding and discrimination Liquid Xenon Ionization + scintillation 2 breakthroughs: ✴ Extraction of electrons from the liquid to the gas ✴At low energy, separation between electron recoils and nuclear recoils increases => work down to ≈4.5 photo electrons with 99% electron rejection efficiency with 50% nuclear recoil efficiency Log (Ionization/Scintillation) Liquid Argon (or Neon) D. McKinzey For light liquids, one additional handle : rise time Triplet (long decay time) killed by nuclear recoil Dark Matter searches Neutrinos 2008 30 May 08 9 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3.Phonon mediated 4.DAMA Xenon 10 S2 ≈3000 p.e. S1 ≈8 p.e. Liquid Xenon: Scintillation + ionization two photon pulses => depth Main differences with Zeplin II: Smaller Photomultipliers Photomultipliers in liquid Dark Matter searches Neutrinos 2008 30 May 08 10 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3.Phonon mediated 4.DAMA Noble Liquids Great progress! -40 10 http://dmtools.brown.edu/ Gaitskell,Mandic,Filippini DATA listed top to bottom on plot CDMS (Soudan) 2005 Si (7 keV threshold) CRESST 2004 10.7 kg-day CaWO4 Edelweiss I final limit, 62 kg-days Ge 2000+2002+2003 limit -41 WARP 2.3L, 96.5 kg-days 55 keV threshold 10 ZEPLIN II (Jan 2007) result CDMS (Soudan) 2004 + 2005 Ge (7 keV threshold) XENON10 2007 (Net 136 kg-d) x x x Linear Collider Cosmology Benchmarks (preliminary) Roszkowski/Ruiz de Austri/Trotta 2007, CMSSM Markov Chain Monte Carlos (mu>0): 68% contour Roszkowski/Ruiz de Austri/Trotta 2007, CMSSM Markov Chain Monte Carlos (mu>0): 95% contour -42 WARP x x x Ellis et. al Theory region post-LEP benchmark points Baltz and Gondolo, 2004, Markov Chain Monte Carlos 10 080318025800 ] (normalised to nucleon) 2 ZEPLIN II -43 10 Xenon 10 2007 Cross-section [cm -44 10 080318025800 1 2 3 10 10 10 WIMP Mass [GeV/c2] y t i What about our 3 challenges v i t • Understand/Calibrate detectors i s s ? n e • Be background free e n se s s ns ? it iti g v much more sensitive than iv ity o l i ∝ ty MT background subtraction ∝ eventually limited by systematics M T sensitivity ∝ constant • Increase mass √ log(exposure=target mass M × time T) Dark Matter searches Neutrinos 2008 30 May 08 11 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3.Phonon mediated 4.DAMA e.g. Xenon 10 After pattern recognition, 10 background events with 50% nuclear recoil efficiency Very nice result but: Large gap at small energy Could it be disguised threshold CDMS Why no flaring of electron at low S1? Detector used in a region Xenon 10 with no calibration Large uncertainty CDMS estimate July 2007 Dark Matter searches Neutrinos 2008 30 May 08 12 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3.Phonon mediated 4.DAMA Noble Liquids: Current Plans Single phase detectors Xenon: Rely on self shielding + position reconstruction: XMASS 800kg Argon: Rely on pulse shape discrimination: DEAP/Mini Clean Lux 300kg Xenon 100kg Dual phase Xenon Xenon 100 : Assembly being finished in Gran Sasso (170kg- 50kg fiducual) LUX 300kg : SUSEL (Homestake) Summer 09 Dual phase Argon WARP ArDM WARP 140kg: Assembly nearly finished ArDM: Being assembled WARP 140kg in A clear danger “My detector is bigger than yours!” Not the whole story: Detailed understanding of the phenomenology Zero background! Dark Matter searches Neutrinos 2008 30 May 08 13 B.Sadoulet 1.