TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAA A A A A A

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) TexPoint fonts used in EMF. Read the TexPoint manual before you delete this box.: AAA A A A A A [Based on Lola, Osland, ARR, Phys. Lett. B656, (2007), arXiv: ]

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Main Points Motivation: SUSY & R-parity Violation The Candidate: Gravitino Dark Matter Three-body vs. radiative gravitino decays Cosmological (and other) constraints Conclusions

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Why do we like SUSY? SUSY MSSM NMSSM CMSSM GMSB AMSB Split SUSY One motivation:(Good) Dark Matter candidates.

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Why do we like SUSY?

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge 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]

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge R-parity violation A priori, the so-called R-parity violating terms are allowed in the superpotential.

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge 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?

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge 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?

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Gravitino Dark Matter With a gravitino LSP the DM lifetime goes as which 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: [G. Bertone et al., arXiv: ] [W. Buchmuller et al., hep-ph/ ] [Lola, Osland, ARR, arXiv: ] [R. Cowen, Science News 172 (2007)] [V.S. Berezinsky, 1991] [M. Taoso et al., arXiv: ] [H. Yuksel, M.D. Kistler, arXiv: ]

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Gravitino Dark Matter [Moreau, Chemtob, hep-ph/ ] The three-body gravitino decay has been calculated Decay suppressed by Planck mass R-violating coupling Three-body phase space Sfermion mass Fermion final state mass (light gravitino)

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Gravitino Dark Matter [Lola, Osland, ARR, arXiv: ] We have calculated the radiative gravitino decay Decay suppressed by Planck mass R-violating coupling Loop factors

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Three-body vs. radiative [Lola, Osland, ARR, arXiv: ] Radiative decay dominates for low gravitino masses:

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Constraints on GDM Measured Dark Matter density –Thermal production of gravitinos after inflation dependent on reheating temperature. –Can well be in correct range.

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Constraints on GDM Measured Dark Matter density Big Bang Nucleosynthesis –Long lived NLSP problem avoided by RPV.

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge 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.

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge 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.

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge 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.

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Constraints on GDM [P. Sreekumar et al., astro-ph/ ] Photon flux taken from EGRET data [G. Bertone et al., arXiv: ] Recent re-analysis: [A.W. Strong et al., astro-ph/ ]

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Constraints on GDM We set limits on dominant RPV coupling vs. gravitino mass. [Lola, Osland, ARR, arXiv: ] Using photon flux taken from EGRET data.

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge 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!

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Phenomenology at the LHC Large variety of signatures depending on dominant RPV-coupling. Most NLSP/RPV-coupling combinations not fully reconstructable due to neutrinos.

Spaatind 2008Dark Matter Shining LightAre R. Raklev University of Cambridge Insensitivity to sfermion mass Gravitino-sfermion- fermion vertex: depends on loop 4-momentum