TexPoint fonts used in EMF.

1. TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAAAAAA

2. Dark Matter Shining Light- Gravitino Dark Matter and R-parity Violation Are R. Raklev University of Cambridge In collaboration with Magda Lola (Patras)and Per Osland (Bergen) [Based on Lola, Osland, ARR, Phys.Lett.B656, 83-90 (2007), arXiv:0707.2510] TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAAAAAAA

3. Main Points • Motivation: SUSY & R-parity Violation • The Candidate: Gravitino Dark Matter • Three-body vs. radiative gravitino decays • Cosmological (and other) constraints • Conclusions Dark Matter Shining Light

4. Why do we like SUSY? SUSY MSSM GMSB CMSSM NMSSM Split SUSY AMSB One motivation: (Good) Dark Matter candidates. Dark Matter Shining Light

5. Why do we like SUSY? Dark Matter Shining Light

6. Why do we like SUSY? • It (sort of) solves the Higgs fine-tuning problem: • It can provide GUT scale unification: [Amaldi, de Boer, Fürstenau, 1991] Dark Matter Shining Light

7. R-parity violation • A priori, the so-called R-parity violating terms are allowed in the superpotential. Dark Matter Shining Light

8. R-parity violation • However, the R-parity violating (RPV) terms are problematic: • Violate lepton and baryon number. • Leads to rapid proton decay. • No SUSY Dark Matter candidate? Dark Matter Shining Light

9. R-parity violation • However, the R-parity violating (RPV) terms are problematic: • Violate lepton and baryon number. • Leads to rapid proton decay. • No SUSY Dark Matter candidate? • And why should the couplings be exactly zero? Dark Matter Shining Light

10. Gravitino Dark Matter • With a gravitino LSP the DM lifetime goes aswhich is easily orders of magnitude above the age of the universe! • The idea has been around for some time – but not recieved much attention until recently: [V.S. Berezinsky, 1991] [W. Buchmuller et al., hep-ph/0702184] [H. Yuksel, M.D. Kistler, arXiv:0711.2906] [Lola, Osland, ARR, arXiv:0707.2510] [M. Taoso et al., arXiv:0711.4996] [G. Bertone et al., arXiv:0709.2299] [R. Cowen, Science News 172 (2007)] Dark Matter Shining Light

11. Gravitino Dark Matter The three-body gravitino decay has been calculated [Moreau, Chemtob, hep-ph/0107286] • Decay suppressed by • Planck mass • R-violating coupling • Three-body phase space • Sfermion mass • Fermion final state mass (light gravitino) Dark Matter Shining Light

12. Gravitino Dark Matter We have calculated the radiative gravitino decay [Lola, Osland, ARR, arXiv:0707.2510] • Decay suppressed by • Planck mass • R-violating coupling • Loop factors Dark Matter Shining Light

13. Three-body vs. radiative Radiative decay dominates for low gravitino masses: [Lola, Osland, ARR, arXiv:0707.2510] Dark Matter Shining Light

14. Constraints on GDM • Measured Dark Matter density • Thermal production of gravitinos after inflation dependent on reheating temperature. • Can well be in correct range. Dark Matter Shining Light

15. Constraints on GDM • Measured Dark Matter density • Big Bang Nucleosynthesis • Long lived NLSP problem avoided by RPV. Dark Matter Shining Light

16. Constraints on GDM • Measured Dark Matter density • Big Bang Nucleosynthesis • Genesis • Baryo-/Leptogenesis may be washed out if RPV strong enough at electroweak phase transition. • Flavour effects may help. Dark Matter Shining Light

17. Constraints on GDM • Measured Dark Matter density • Big Bang Nucleosynthesis • Genesis • Neutrino masses • RPV couplings can give rise to neutrino masses. • Gives restrictions on RPV couplings. • May explain measured masses. Dark Matter Shining Light

18. Constraints on GDM • Measured Dark Matter density • Big Bang Nucleosynthesis • Genesis • Neutrino masses • Photon flux (!) • Measurement of galactic and diffuse extra-galactic gamma ray flux constrains radiative decays. • Perhaps also interesting to look at 511 keV line. Dark Matter Shining Light

19. Constraints on GDM Photon flux taken from EGRET data [P. Sreekumar et al., astro-ph/9709257] Recent re-analysis: [A.W. Strong et al., astro-ph/0406254] [G. Bertone et al., arXiv:0709.2299] Dark Matter Shining Light

20. Constraints on GDM We set limits on dominant RPV coupling vs. gravitino mass. Using photon flux taken from EGRET data. [Lola, Osland, ARR, arXiv:0707.2510] Dark Matter Shining Light

21. Conclusions • The gravitino is a possible Dark Matter candidate even with large RPV couplings. • For light(ish) gravitinos, radiative loop decays are important and even dominant. • Measurements of photon flux set strict upper bounds on RPV couplings in these scenarios. • We could discover Dark Matter by the light from its decays! Dark Matter Shining Light

22. Phenomenology at the LHC Large variety of signatures dependingon dominant RPV-coupling. Most NLSP/RPV-coupling combinations not fully reconstructable due to neutrinos. Dark Matter Shining Light

23. Insensitivity to sfermion mass Gravitino-sfermion-fermion vertex: depends on loop 4-momentum Dark Matter Shining Light