1. 12/9/04KICP - Spin Dependent Limits 1 Can WIMP Spin Dependent Couplings explain DAMA? Limits from DAMA and Other Experiments Christopher M. Savage University of Michigan – Ann Arbor Katie Freese (University of Michigan) Paolo Gondolo (University of Utah) astro-ph/0408346 to appear in Phys. Rev. D

2. 12/9/04KICP - Spin Dependent Limits 2 Overview DAMA/NaI positive signal and CDMS II null result are not compatible for spin-independent couplings (assuming the standard halo model) With exceptions – Gelmini & Gondolo (2004) WIMPs may alternatively have spin-dependent couplings; examine if this case has parameter space consistent with the DAMA signal and the null results of other experiments P. Ullio, M. Kamionkowski, and P. Vogel, JHEP 0107, 044 (2001). F. Giuliani, arXiv:hep-ph/0404010.

3. 12/9/04KICP - Spin Dependent Limits 3 Direct Detection Elastic scattering of WIMP off detector nuclei Rate: Recoils: Efficiencies, quenching, multiple elements CDMS, CRESST, Edelweiss, SIMPLE, ZEPLIN, NAIAD, etc. Detector WIMP Scatter Goodman &Witten (1985)

4. 12/9/04KICP - Spin Dependent Limits 4 Annual Modulation Earth’s motion With disk (June) Against disk (December) Modulation Amplitude: DAMA (R. Bernabei et al., 2003) N ma = 0.0200 ± 0.0032 /kg/day/keVee (2-6 keVee) Elegant V, etc. 30 km/s 232 km/s WIMP Halo Wind Drukier, Freese & Spergel (1986)

5. 12/9/04KICP - Spin Dependent Limits 5 Indirect Detection Gravitational capture  Annihilation Neutrino-induced muons Sun: WIMP-proton cross-section Baksan, Super-K, ANTARES, etc. WIMP  anti-WIMP, asymmetry Halo model dependence WIMP Silk, Olive & Srednicki (1985) Freese (1986)

6. 12/9/04KICP - Spin Dependent Limits 6 Spin-Dependent Cross-Section Nuclear structure functions Odd proton: S pp >> S nn Odd neutron: S nn >> S pp Finite momentum transfer q = 0   SD  (  a p +  a n ) 2  ( a p + a n ) 2 q  0 : larger masses

7. 12/9/04KICP - Spin Dependent Limits 7 Spin-Dependent Limits Null Result: Positive Signal: A, B, C Depend on detector parameters, WIMP mass Relative magnitude dependent upon S pp, S pn, S nn Conics Parallel lines Ellipse OGMEOGM q  0 Multiple Elements

8. 12/9/04KICP - Spin Dependent Limits 8 Spin-Dependent Limits Proton only coupling ( a n = 0 ) Neutron only coupling ( a p = 0 ) General couplings

9. 12/9/04KICP - Spin Dependent Limits 9 WIMP-Proton Cross-Section Limits (for a n = 0 ) NAIAD, etc.

10. 12/9/04KICP - Spin Dependent Limits 10 WIMP-Neutron Cross-Section Limits (for a p = 0 ) Zeplin I (Preliminary) V. Kudryavtsev et al., IDM 2004 a p = -3

11. 12/9/04KICP - Spin Dependent Limits 11 Allowed Couplings

12. 12/9/04KICP - Spin Dependent Limits 12 Allowed Couplings (Low Mass)

13. 12/9/04KICP - Spin Dependent Limits 13 Results WIMP masses of 5-13 GeV: Parameter spaces still remain which are compatible with DAMA signal and all null results Allows for comparable proton and neutron couplings (e.g. a p = a n = 2.5 at 8 GeV) All solutions have No MSSM candidates  LEP: M  > 30 GeV(Abbiendi et al. [OPAL], 2000)

14. 12/9/04KICP - Spin Dependent Limits 14 Results (12/8) WIMP masses of 5-10 GeV: Super-K extended analysis S. Desai for Super-K (private correspondence)

15. 12/9/04KICP - Spin Dependent Limits 15 Conclusions DAMA can still be explained by a WIMP with spin-dependent couplings, although at masses too low for MSSM. Extending analysis of Super-K (Baksan) results to lower masses could confirm or rule out the remaining spin-dependent parameter space for DAMA (for standard halo) – (IN PROGRESS). Odd-Z experiments (CRESST I, SIMPLE/PICASSO, COUPP,etc.) will also be able to examine this remaining space. Thresholds more important than exposure