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 m < .17eV Large Scale structure+baryon oscillation + Lyman α v 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

Xenon 10 as generic for CDMS as generic for ZEPLIN II ,WARP, ArDM EDELWEISS & CRESST 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 !"#$%&'()$ + New ideas Mini-CLEAN *+#$%&',-.$/ 0 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. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Phonon Mediated Detectors

Principle: Detect lower energy excitations 15 keV large by condensed matter physics standards

Goals Target crystal • Sensitivity down to low energy Phonons measure the full energy • Active rejection of background: recognition of nuclear recoil Combine with low field ionization measurement CDMS EDELWEISS or scintillation (CRESST II) But: operation at very low temperature! e.g. CDMS II: 40mK

3” (7.6 cm)

250x1μm 380x60μm W TES Al fins

1 cm Ge:

x 30= 5 towers of 6

Dark Matter searches Neutrinos 2008 30 May 08 14 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Multidimensional Discrimination Ionization yield Timing -> surface discrimination

Surface Electrons Ionization/Recoil energy Recoil Energy

Neutrons Fix cuts blind ( with calibration sources) Surface evts to get ≈0.5 events background

timing parameter[µs] Dark Matter searches Neutrinos 2008 30 May 08 15 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Opening the Box

Box opened Monday, February 4 for 15 Ge ZIPs Remaining 8 Si and 1 Ge undergoing further leakage characterization

1.5 3σ region masked => Hide unvetoed singles

1

Lift the mask, see 97 Ionization yield singles failing timing cut Ionization yield 0.5

Apply the timing cut, 0 0 20 40 60 80 100 count the candidates Recoil energy (keV)

No events observed

Dark Matter searches Neutrinos 2008 30 May 08 16 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Current WIMP Limits

2 CDMS again-40 in the lead above 40GeV/c 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 WARP x x x Ellis et. al Theory region post-LEP benchmark points -42 Baltz and Gondolo, 2004, Markov Chain Monte Carlos 10 080318025800 ] (normalised to nucleon) 2 ZEPLIN II

-43 10 Xenon 10 2007 CDMS Ge 2008

Cross-section [cm -44 10 080318025800 1 2 3 10 10 10 WIMP Mass [GeV/c2]

Preprint at: •http://cdms.berkeley.edu •arXiv:0802.3530

Dark Matter searches Neutrinos 2008 30 May 08 17 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Immediate Future (cryogenic) CDMS: run till ≈ December 08 ≈2000kg days sensitivity ≈10-44 cm2/nucleon stay background free: - new towers 3 lower back grounds - better discrimination tools Edelweiss-> 10-43 cm 21 330g Ge detectors with NTD + 7 400g Nb Si (athermal phonons) first commissioning run April -May 07 encouraging no event > 30keV for eight NTD detectors (19 kg day) (cf 3 in EdelI) first underground test of two 200g Nb Si Interdigitated detectors

CRESST II-> 10-43 cm Major upgrade 66 SQUIDs for 33 detectors + neutron shield Three detectors running since 4/07.

Dark Matter searches Neutrinos 2008 30 May 08 18 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated Low Temperature Detector Future 4. DAMA

no subtraction --- background subtraction … zero background T1 2004 T1-2 2005 T1-5 2007 CDMS II Goals T1-5 2009 SuperCDMS Soudan 4kg 2009

SuperCDMS Soudan 25kg 2012

SuperCDMS SNOLAB 150kg 2015 y t i v i t i

s s n e Three General 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 19 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Larger Detector Mass

SuperCDMS 25 kg detectors: 1cm-> 1” 250g ->635 g

First tests encouraging (we need to add a radial measurement) Double face 35% -> 70%?

500 Dislocation Free Ge Crystal

120 450

100 Much larger detectors -> 1ton expt?400 80 350 Liquid N2 Ge crystals limited to 3” 60 3 300 ≈ 100 dislocation/cm 40 250 20 Collection Efficiency [%]

But we showed recently that dislocation free 200 0 -3 -2 -1 0 1 2 3 Counts per 0.1 keV bin works at low temperature! 150 Voltage [V] Umicore grows (doped) 8” crystal 100 50

0 6”x2” or 8”x1” ≈ 5kg + Multiplexing 0 10 20 30 40 50 60 70 Energy [keV]

Dark Matter searches Neutrinos 2008 30 May 08 20 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA DAMA Claim April 2008

If WIMPs exist, we dNexpect a modulation in event rate dE Earth June 2 Sun Dec 2 E

Clearly a modulation ≈5.5% Not a WIMP: incompatible with other experiments

Dark Matter searches Neutrinos 2008 30 May 08 21 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Tension with Other Expt.

-40 Spin independent10 interactions

-41 10

-42 10 ] (normalised to nucleon) 2 DATA listed top to bottom on plot Edelweiss I final limit, 62 kg-days Ge 2000+2002+2003 limit -43 DAMA 2000 58k kg-days NaI Ann. Mod. 3sigma w/DAMA 1996 10 WARP 2.3L, 96.5 kg-days 55 keV threshold ZEPLIN II (Jan 2007) result CDMS: 2004+2005 (reanalysis) +2008 Ge XENON10 2007 (Net 136 kg-d)

Cross-section [cm -44 10 1 2 3 10 10 10 WIMP Mass [GeV/c2] “n” scattering “p” scattering

Spin dependent CDMS II Si CRESST I CDMS Si PICASSO DAMA/NaI CDMS II Ge CRESST I PICASSO

CDMS II Si Xenon 10 Prel. ZEPLINI DAMA/NaI NAIAD CDMS II Ge COUPP Xenon 10 Prel. Super-K astro-ph/0509269

Dark Matter searches Neutrinos 2008 30 May 08 22 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA What could it be? An axionic type particle of 3 keV converting its mass into electromagnetic energy in detector Modulation by flux Predict electron recoil line at 3 keV Can be in principle checked by other detectors: being done by CDMS! An effect related to well known modulation of muon flux, which has exactly the same phase Decay path change with temperature!

DAMA claims it cannot be neutrons

What about an unknown 3 keV nuclear line with 2 2 2 lifetime > 2 coincidence time (Spencer Klein)? Measurement by MACRO ≠ Auger in 40K decay

Dark Matter searches Neutrinos 2008 30 May 08 23 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA The overall picture Generically: scalar interactions ≈A2

Current WIMP searches GLAST launched May 08 Next generation

1 generation beyond

Large Hadron Finer and finer Collider Jul 08 tuning to get right density!

Dark Matter searches Neutrinos 2008 30 May 08 248 B.Sadoulet 1. Particle Cosmology 2. Noble liquids 3. Phonon mediated 4. DAMA Conclusions Essential to detect Dark Matter A key ingredient of the standard model of cosmology At least show it is not an epicycle! WIMPs is the generic Thermal model The field of direct detection is very active, many ideas -44 2 We should reach 10 cm /nucleon very soon (2009) -45 2 10 cm /nucleon should be reachable by • phonon mediated detectors • Liquid Xenon 2 phase • Liquid Ar 2 phases+pulse shape maybe other simpler technologies (XMASS, MiniCLEAN, COUPP) -46-47 2 10 cm /nucleon considerable challenge ( ≈ evt/ton/yr) When we have a discovery: link to galaxy (low pressure TPC≈5000 m3 ) Complementarity with accelerators and indirect detection Large Hadron Collider may probe the same physics GLAST could be smoking gun ( Dark Matter + Hierarchical merging) + ICE Cube

We may well be at the brink of discovery! B.Sadoulet, Science 315 (2007) 61

Dark Matter searches Neutrinos 2008 30 May 08 B.Sadoulet Gamma Rays: A smoking gun?

Via Lactea simulation Diemand,Kuhlen,Madau Piero Madau’s talk No gas in simulation

Simulated Glast <= Via Lactea

<σv>=5×10-26 cm3 s-1

MΧ = 46 GeV LSP WIMP (SUSY) 2 years If subhalos are observed GLAST 5-yrs Smoking gun for Dark Matter Hierarchical merging LCC2 Focus Point

LCC4 Coannihilation

Dark Matter searches Neutrinos 2008 30 May 08 B.Sadoulet