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) arXiv:0808.3607 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection Overview DAMA/NaI (1996-2002) 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+) Confirms annual modulation (8.2) Can WIMP scattering still explain both DAMA signal and null results of other experiments? 8/29/08 Cosmo 08 - DAMA and Direct Detection

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

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

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

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

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

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

Cosmo 08 - DAMA and Direct Detection Annual Modulation DAMA/NaI & DAMA/LIBRA (R. Bernabei et al., 2008) Modulation amplitude: Sm = 0.0131 ± 0.0016 /kg/day/keVee (2-6 keVee) 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection Indirect Detection Silk, Olive & Srednicki (1985), Freese (1986) Elastic scattering of WIMP off Sun/Earth nuclei  gravitational capture  annihilation (neutrinos) Flux   X X = H, He, … SuperK, AMANDA/IceCube, etc. n WIMP 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection Indirect Detection Cross-sections Gravitational capture  scattering Annihilation  ann Assumptions No large WIMP/anti-WIMP asymmetry Annihilation cross-section large “enough” Annihilation not to light quarks Majorana () Relic abundance <ann v> ~ 10-26 cm3/s Majorana () 8/29/08 Cosmo 08 - DAMA and Direct Detection

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

Scattering Cross-Section Spin-independent (SI) Couples to scalar density of quarks and gluons Scales as A2 MSSM: fp  fn  only one parameter: SI,p Spin-dependent (SD) Couples to spin Multiple form factors due to spins of proton and neutron groups Does not scale with A 8/29/08 Cosmo 08 - DAMA and Direct Detection

Scattering Cross-Section Total Couplings 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 Indirect detection: Sun is primarily hydrogen Direct detection: SI A2 boost 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection DAMA Modulation DAMA/NaI (1996-2002) R. Bernabei et al., Riv. Nuovo Cim. 26N1, 1 (2003) Observes annual modulation (6.3)  first claimed signal for direct detection of WIMPs DAMA/LIBRA (2003+) R. Bernabei et al., arXiv:0804.2741 [astro-ph] Confirms annual modulation (8.2) 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection DAMA Modulation DAMA/NaI (6.3) Bernabei et al. (2003) 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection DAMA Modulation DAMA/NaI + DAMA/LIBRA (8.2) Bernabei et al. (2008) 8/29/08 Cosmo 08 - DAMA and Direct Detection

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

Cosmo 08 - DAMA and Direct Detection DAMA Modulation Requirements for DM signal Cosine modulation 1 year period Phase ~ June 2nd (standard halo) Modulation at low energies only Modulation in single scatter events only (not in multiples) Modulation amplitude  ~7% Multiple hits 2-6 keVee -0.0004 ± 0.0006 cpd/kg/keVee High energies 90+ keV -0.05 ± 0.19 cpd/kg (one cycle) 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection DAMA Modulation Backgrounds/systematics 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

Cosmo 08 - DAMA and Direct Detection DAMA/NaI Incompatible? Standard framework Spin-independent Isothermal halo Cutoff: mass > 30 GeV 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection DAMA/NaI Explanations/effects Low mass WIMPs P. Gondolo & G. Gelmini, PRD 71, 123520 (2005) Streams/caustics Gondolo & Gelmini (Ibid) 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) Inelastic scattering D. Tucker-Smith & N. Weiner, PRD 72, 063509 (2005) Mirror matter R. Foot, PRD 74, 023514 (2006) Etc. Channeling effect Migdal effect 8/29/08 Cosmo 08 - DAMA and Direct Detection

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

Cosmo 08 - DAMA and Direct Detection Spin-dependent 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

Cosmo 08 - DAMA and Direct Detection Channeling Nuclear recoil energy (keV) Electrons – ionization/scintillation electron equivalent (keVee) Other nuclei – phonons/heat Quenching factor Q: fraction of recoil energy into measured channel QNa  0.3, QI  0.09  2 keVee DAMA event from: 6.7 keV Na recoil 22 keV I recoil 8/29/08 Cosmo 08 - DAMA and Direct Detection

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

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

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

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

Cosmo 08 - DAMA and Direct Detection DAMA/LIBRA DAMA/LIBRA analyses (selected) CS, G. Gelmini, P. Gondolo & K. Freese, arXiv:0808.3607 [astro-ph] F. Petriello & K.M. Zurek, arXiv:0806.3989 [hep-ph] S. Chang, A. Pierce & N. Weiner, arXiv:0808.0196 [hep-ph] D. Hooper, F. Petriello, K.M. Zurek & M. Kamionkowski, arXiv:0808.2464 [hep-ph] Assumptions Isothermal spherical halo model Elastic scattering 8/29/08 Cosmo 08 - DAMA and Direct Detection

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

Cosmo 08 - DAMA and Direct Detection DAMA Binning DAMA/NaI: 2 bins Low energy 2-4 keVee 0.0252 ± 0.0050 cpd/kg/keVee 2-5 keVee 0.0215 ± 0.0039 cpd/kg/keVee 2-6 keVee 0.0200 ± 0.0032 cpd/kg/keVee High energy 6-14 keVee -0.0009 ± 0.0019 cpd/kg/keVee DAMA/NaI + DAMA/LIBRA: 36 bins Low energy (2-5 keVee): positive modulation signal High energy (~6-20 keVee): consistent with zero modulation 8/29/08 Cosmo 08 - DAMA and Direct Detection

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Cosmo 08 - DAMA and Direct Detection SuperK Analysis Original: S. Desai et al. [SuperK Collaboration], PRD 70, 083523 (2004) Analysis down to 10 GeV WIMP mass No neutrino oscillations Reanalysis: D. Hooper, F. Petriello, K.M. Zurek & M. Kamionkowski, arXiv:0808.2464 [hep-ph] Low WIMP masses Neutrino Oscillations Spin-independent Talk by Kathryn Zurek 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection (from Kathryn Zurek) SuperK Analysis 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection (from Kathryn Zurek) SuperK Analysis 8/29/08 Cosmo 08 - DAMA and Direct Detection

Cosmo 08 - DAMA and Direct Detection Results Parameter spaces still remain which are compatible with DAMA signal and all null results Spin-independent: 7-10 GeV (SuperK constrained) Spin-dependent (proton only): 3-10 GeV (SuperK constrained) Spin-dependent (neutron only): 7-9 GeV Spin-dependent (mixed): 3-10 GeV (SuperK constrained) Allows for comparable proton and neutron couplings (e.g. ap = an = 2.5 at 5 GeV) 8/29/08 Cosmo 08 - DAMA and Direct Detection

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