Broken R-Parity in the Sky and at the LHC

Abstract

Supersymmetric extensions of the Standard Model with small R-parity and lepton number violating couplings are naturally consistent with primordial nucleosynthesis, thermal leptogenesis and gravitino dark matter. We consider supergravity models with universal boundary conditions at the grand unification scale, and scalar tau-lepton or bino-like neutralino as next-to-lightest superparticle (NLSP). Recent Fermi-LAT data on the isotropic diffuse gamma-ray flux yield a lower bound on the gravitino lifetime. Comparing two-body gravitino and neutralino decays we find a lower bound on a neutralino NLSP decay length, $c τ_{χ^0_1} \gsim 30 cm$. Together with gravitino and neutralino masses one obtains a microscopic determination of the Planck mass. For a stau-NLSP there exists no model-independent lower bound on the decay length. Here the strongest bound comes from the requirement that the cosmological baryon asymmetry is not washed out, which yields $c τ_{\tildeτ_1} \gsim 4 mm$. However, without fine-tuning of parameters, one finds much larger decay lengths. For typical masses, $m_{3/2}\sim 100GeV$ and $m_{NLSP}\sim 150GeV$, the discovery of a photon line with an intensity close to the Fermi-LAT limit would imply a decay length $c{\tau }_{NLSP}$ of several hundred meters, which can be measured at the LHC.

30 pages, 8 figures; v2: published version, reference added

References in corpus (9)

• Big Bang Nucleosynthesis Constraints on Hadronically and Electromagnetically Decaying Relic Neutral Particles
• Gamma Ray Spectrum from Gravitino Dark Matter Decay
• High Energy Cosmic Rays from the Decay of Gravitino Dark Matter
• Gamma-Rays from Decaying Dark Matter
• Probing bilinear R-parity violating supergravity at the LHC
• Radiative gravitino decays from R-parity violation
• Probing Gravitino Dark Matter with PAMELA and Fermi
• Measuring lifetimes of long-lived charged massive particles stopped in LHC detectors
• Long-Lived Unstable Superparticles at the LHC

Cited by in corpus (3)

• Stau as the Lightest Supersymmetric Particle in R-Parity Violating SUSY Models: Discovery Potential with Early LHC Data
• Dynamical Matter-Parity Breaking and Gravitino Dark Matter
• Dynamical R-parity Breaking at the LHC