The Status of DAMA and Direct Detection of

The Status of DAMA and Direct Detection of WIMPs Limits from DAMA and Other Experiments Christopher M. Savage Fine Theoretical Physics Institute University of Minnesota Katie Freese (University of Michigan) Graciela Gelmini (UCLA) Paolo Gondolo (University of Utah) ar. Xiv: 0808. 3607 8/29/08 Cosmo 08 - DAMA and Direct Detection 1

Overview n DAMA/Na. I (1996 -2002) l l l n Observes annual modulation (6. 3 ) first claimed signal for direct detection of WIMPs Apparent incompatibilities with other experiments in standard frameworks Many proposed explanations, including spin-dependent couplings DAMA/LIBRA (2003+) l l 8/29/08 Confirms annual modulation (8. 2 ) Can WIMP scattering still explain both DAMA signal and null results of other experiments? Cosmo 08 - DAMA and Direct Detection 2

Outline n WIMP direct detection & modulation n DAMA modulation signal n Explanations and detector effects n Compatibility with other experiments (effective WIMP-nucleon couplings) 8/29/08 Cosmo 08 - DAMA and Direct Detection 3

Elastic Scattering and WIMP Detection n Direct detection n Annual modulation n Indirect detection (Sun/Earth) 8/29/08 Cosmo 08 - DAMA and Direct Detection 4

Direct Detection Talk by Uwe Oberlack Goodman & Witten (1985) n Detector WIMP Elastic scattering of WIMP off detector nuclei Scatter n Rate: n Recoils: n Efficiencies, quenching, multiple elements l 8/29/08 WIMP X = Ge, Xe, … CDMS, XENON, CRESST, TEXONO, Co. Ge. NT, COUPP, etc. Cosmo 08 - DAMA and Direct Detection 5

Direct Detection n Recoil spectrum 8/29/08 Cosmo 08 - DAMA and Direct Detection 6

Annual Modulation WIMP Halo Wind 30 km/s Drukier, Freese & Spergel (1986) n Earth’s motion l 8/29/08 With disk (June) Against disk (December) ~300 km/s Cosmo 08 - DAMA and Direct Detection 7

Annual Modulation 8/29/08 Cosmo 08 - DAMA and Direct Detection 8

Annual Modulation n DAMA/Na. I & DAMA/LIBRA (R. Bernabei et al. , 2008) Modulation amplitude: Sm = 0. 0131 ± 0. 0016 /kg/day/ke. Vee (2 -6 ke. Vee) 8/29/08 Cosmo 08 - DAMA and Direct Detection 9

Indirect Detection Silk, Olive & Srednicki (1985), Freese (1986) l l Elastic scattering of WIMP off Sun/Earth nuclei gravitational capture annihilation (neutrinos) Flux X n X = H, He, … WIMP l 8/29/08 Super. K, AMANDA/Ice. Cube, etc. Cosmo 08 - DAMA and Direct Detection 10

Indirect Detection n Cross-sections l l n Gravitational capture Annihilation scattering ann Assumptions 8/29/08 l No large WIMP/anti-WIMP asymmetry l Annihilation cross-section large “enough” l Annihilation not to light quarks Cosmo 08 - DAMA and Direct Detection Majorana ( ) Relic abundance < ann v> ~ 10 -26 cm 3/s Majorana ( ) 11

Effective Coupling n Effective Lagrangian ( -quark): Axial vector (spin-dependent) n Scalar (spin-independent) SUSY 2 q, 3 q 8/29/08 Cosmo 08 - DAMA and Direct Detection 12

Scattering Cross-Section n Spin-independent (SI) § § § n Couples to scalar density of quarks and gluons Scales as A 2 MSSM: fp fn only one parameter: SI, p Spin-dependent (SD) § § § 8/29/08 Couples to spin Multiple form factors due to spins of proton and neutron groups Does not scale with A Cosmo 08 - DAMA and Direct Detection 13

Scattering Cross-Section n Total n Couplings l n fp , fn , ap , an SI, p , SI, n , SD, p , SD, n (+ 2 signs) SD scattering cross-section for a nucleon typically much larger (102 - 104+) than SI cross-section in CMSSM l l 8/29/08 Indirect detection: Sun is primarily hydrogen Direct detection: SI A 2 boost Cosmo 08 - DAMA and Direct Detection 14

DAMA Modulation n DAMA/Na. I (1996 -2002) R. Bernabei et al. , Riv. Nuovo Cim. 26 N 1, 1 (2003) l n Observes annual modulation (6. 3 ) first claimed signal for direct detection of WIMPs DAMA/LIBRA (2003+) R. Bernabei et al. , ar. Xiv: 0804. 2741 [astro-ph] l 8/29/08 Confirms annual modulation (8. 2 ) Cosmo 08 - DAMA and Direct Detection 15

DAMA Modulation n DAMA/Na. I (6. 3 ) Bernabei et al. (2003) 8/29/08 Cosmo 08 - DAMA and Direct Detection 16

DAMA Modulation n DAMA/Na. I + DAMA/LIBRA (8. 2 ) Bernabei et al. (2008) 8/29/08 Cosmo 08 - DAMA and Direct Detection 17

DAMA Modulation 8/29/08 Cosmo 08 - DAMA and Direct Detection 18

DAMA Modulation n n Requirements for DM signal 1) Cosine modulation 2) 1 year period 3) Phase ~ June 2 nd (standard halo) 4) Modulation at low energies only 5) Modulation in single scatter events only (not in multiples) 6) Modulation amplitude ~7% Multiple hits 2 -6 ke. Vee n -0. 0004 ± 0. 0006 cpd/kg/ke. Vee High energies l 8/29/08 90+ ke. V -0. 05 ± 0. 19 cpd/kg (one cycle) Cosmo 08 - DAMA and Direct Detection 19

DAMA Modulation n Backgrounds/systematics l l l n Temperature Neutrons + other backgrounds Radon Muon flux modulation Detector noise None reproduce all signal characteristics or capable of producing level of signal 8/29/08 Cosmo 08 - DAMA and Direct Detection 20

DAMA/Na. I n Incompatible? n Standard framework l l n Spin-independent Isothermal halo Cutoff: mass > 30 Ge. V 8/29/08 Cosmo 08 - DAMA and Direct Detection 21

DAMA/Na. I n Explanations/effects l Low mass WIMPs • P. Gondolo & G. Gelmini, PRD 71, 123520 (2005) l Streams/caustics • Gondolo & Gelmini (Ibid) l Spin-dependent couplings • CS, P. Gondolo & K. Freese, PRD 70, 123513 (2004) • F. Giuliani & T. A. Girard, PRD 71, 123503 (2005) • P. Ullio, M. Kamionkowski & P. Vogel, JHEP 0107, 044 (2001) l Inelastic scattering • D. Tucker-Smith & N. Weiner, PRD 72, 063509 (2005) l Mirror matter • R. Foot, PRD 74, 023514 (2006) l Etc. l Channeling effect Migdal effect l 8/29/08 Cosmo 08 - DAMA and Direct Detection 22

Low mass WIMPs l Relax 30 Ge. V mass cut – scattering off Na P. Gondolo & G. Gelmini, PRD 71, 123520 (2005) 8/29/08 Cosmo 08 - DAMA and Direct Detection 23

Spin-dependent l Spin-dependent couplings CS, P. Gondolo & K. Freese, PRD 70, 123513 (2004) F. Giuliani & T. A. Girard, PRD 71, 123503 (2005) P. Ullio, M. Kamionkowski & P. Vogel, JHEP 0107, 044 (2001) 8/29/08 Cosmo 08 - DAMA and Direct Detection 24

Channeling n Nuclear recoil energy (ke. V) l Electrons – ionization/scintillation § l n electron equivalent (ke. Vee) Other nuclei – phonons/heat Quenching factor Q: l l fraction of recoil energy into measured channel QNa 0. 3, QI 0. 09 2 ke. Vee DAMA event from: • • 8/29/08 6. 7 ke. V Na recoil 22 ke. V I recoil Cosmo 08 - DAMA and Direct Detection 25

Channeling n Ion channeling l l 8/29/08 (R. Bernabei et al. , 2008) Recoils along channels in crystal Energy dependent fraction of recoils have Q 1 Cosmo 08 - DAMA and Direct Detection 26

DAMA Channeling 8/29/08 Bernabei et al. (2008) Cosmo 08 - DAMA and Direct Detection 27

Migdal Effect Migdal (1941) l l 8/29/08 Velocity change of recoiling nucleus excited/ionized electrons Bernabei et al. (2007) Extra EM energy (ionization/scintillation) Cosmo 08 - DAMA and Direct Detection 28

DAMA Migdal Effect 8/29/08 Bernabei et al. (2008) Cosmo 08 - DAMA and Direct Detection 29

DAMA/LIBRA n n DAMA/LIBRA analyses (selected) § CS, G. Gelmini, P. Gondolo & K. Freese, ar. Xiv: 0808. 3607 [astro-ph] § F. Petriello & K. M. Zurek, ar. Xiv: 0806. 3989 [hep-ph] § S. Chang, A. Pierce & N. Weiner, ar. Xiv: 0808. 0196 [hep-ph] § D. Hooper, F. Petriello, K. M. Zurek & M. Kamionkowski, ar. Xiv: 0808. 2464 [hep-ph] Assumptions l l 8/29/08 Isothermal spherical halo model Elastic scattering Cosmo 08 - DAMA and Direct Detection 30

DAMA/LIBRA n Binning n Channeling n Statistical methods n Spin-independent (SI) n Spin-dependent (SD) l l 8/29/08 Proton-only coupling (an = 0) Neutron-only coupling (ap = 0) Equal magnitude (an = ±ap) General couplings Cosmo 08 - DAMA and Direct Detection 31

DAMA Binning n DAMA/Na. I: 2 bins l Low energy § § § l 0. 0252 ± 0. 0050 cpd/kg/ke. Vee 0. 0215 ± 0. 0039 cpd/kg/ke. Vee 0. 0200 ± 0. 0032 cpd/kg/ke. Vee High energy § n 2 -4 ke. Vee 2 -5 ke. Vee 2 -6 ke. Vee 6 -14 ke. Vee -0. 0009 ± 0. 0019 cpd/kg/ke. Vee DAMA/Na. I + DAMA/LIBRA: 36 bins l l 8/29/08 Low energy (2 -5 ke. Vee): positive modulation signal High energy (~6 -20 ke. Vee): consistent with zero modulation Cosmo 08 - DAMA and Direct Detection 32

DAMA Binning 8/29/08 Cosmo 08 - DAMA and Direct Detection 33

DAMA Binning 8/29/08 Cosmo 08 - DAMA and Direct Detection 34

DAMA Binning 8/29/08 Cosmo 08 - DAMA and Direct Detection 35

DAMA Channeling 8/29/08 Cosmo 08 - DAMA and Direct Detection 36

DAMA Channeling 8/29/08 Cosmo 08 - DAMA and Direct Detection 37

DAMA Statistical Tests n Likelihood ratio confidence region l n Parameter estimation – preferred region 2 goodness of fit (g. o. f. ) l 8/29/08 Excluded region Cosmo 08 - DAMA and Direct Detection 38

DAMA Statistical Tests 8/29/08 Cosmo 08 - DAMA and Direct Detection 39

DAMA Statistical Tests 8/29/08 Cosmo 08 - DAMA and Direct Detection 40

Null Experiments 8/29/08 Cosmo 08 - DAMA and Direct Detection 41

Spin-independent 8/29/08 Cosmo 08 - DAMA and Direct Detection 42

Spin-independent 8/29/08 Cosmo 08 - DAMA and Direct Detection 43

Spin-independent 8/29/08 Cosmo 08 - DAMA and Direct Detection 44

Spin-dependent: proton-only (an = 0) 8/29/08 Cosmo 08 - DAMA and Direct Detection 45

Spin-dependent: proton-only (an = 0) 8/29/08 Cosmo 08 - DAMA and Direct Detection 46

Spin-dependent: proton-only (an = 0) 8/29/08 Cosmo 08 - DAMA and Direct Detection 47

Spin-dependent: neutron-only (ap = 0) 8/29/08 Cosmo 08 - DAMA and Direct Detection 48

Spin-dependent: neutron-only (ap = 0) 8/29/08 Cosmo 08 - DAMA and Direct Detection 49

Spin-dependent: neutron-only (ap = 0) 8/29/08 Cosmo 08 - DAMA and Direct Detection 50

Spin-dependent (an = ap) 8/29/08 Cosmo 08 - DAMA and Direct Detection 51

Spin-dependent (an = ap) 8/29/08 Cosmo 08 - DAMA and Direct Detection 52

Spin-dependent (an = -ap) 8/29/08 Cosmo 08 - DAMA and Direct Detection 53

Spin-dependent (an = -ap) 8/29/08 Cosmo 08 - DAMA and Direct Detection 54

a=2 a = 20 Spin-dependent couplings 8/29/08 Cosmo 08 - DAMA and Direct Detection N 1 pb N 100 pb 55

a=2 a = 20 Spin-dependent couplings 8/29/08 Cosmo 08 - DAMA and Direct Detection N 1 pb N 100 pb 56

Super. K Analysis n Original: S. Desai et al. [Super. K Collaboration], PRD 70, 083523 (2004) § § n Analysis down to 10 Ge. V WIMP mass No neutrino oscillations Reanalysis: D. Hooper, F. Petriello, K. M. Zurek & M. Kamionkowski, ar. Xiv: 0808. 2464 [hep-ph] § § § 8/29/08 Low WIMP masses Neutrino Oscillations Spin-independent Talk by Kathryn Zurek Cosmo 08 - DAMA and Direct Detection 57

Super. K Analysis 8/29/08 (from Kathryn Zurek) Cosmo 08 - DAMA and Direct Detection 58

Super. K Analysis 8/29/08 (from Kathryn Zurek) Cosmo 08 - DAMA and Direct Detection 59

Results n Parameter spaces still remain which are compatible with DAMA signal and all null results § § n Spin-independent: Spin-dependent (proton only): Spin-dependent (neutron only): Spin-dependent (mixed): 7 -10 Ge. V (Super. K constrained) 3 -10 Ge. V (Super. K constrained) 7 -9 Ge. V 3 -10 Ge. V (Super. K constrained) Allows for comparable proton and neutron couplings (e. g. ap = an = 2. 5 at 5 Ge. V) 8/29/08 Cosmo 08 - DAMA and Direct Detection 60

Conclusions n DAMA can still be explained by low mass WIMPs with spinindependent and/or spin-dependent couplings l n Super. K further constrains couplings (if valid) l n Isothermal halo Spin-dependent neutron coupling survives Probing compatible parameter space: l l 8/29/08 Odd-Z experiments (SIMPLE/PICASSO, COUPP, KIMS, etc. ) Thresholds more important than exposure Cosmo 08 - DAMA and Direct Detection 61