Superparticle Mass Window from Leptogenesis and Decaying Gravitino Dark Matter

TL;DR

This paper explores how gravitino dark matter and thermal leptogenesis impose constraints on superparticle masses, predicting a detectable mass window at the LHC and specific cosmic ray signatures.

Contribution

It provides a detailed analysis of supergravity models with universal boundary conditions, identifying a superparticle mass window consistent with cosmological and collider constraints.

Findings

Superparticle masses are constrained to a specific window compatible with leptogenesis.

Decaying gravitinos produce characteristic high-energy cosmic ray signatures.

Reheating temperatures are bounded within a range compatible with cosmological observations.

Abstract

Gravitino dark matter, together with thermal leptogenesis, implies an upper bound on the masses of superparticles. In the case of broken R-parity the constraints from primordial nucleosynthesis are naturally satisfied and decaying gravitinos lead to characteristic signatures in high energy cosmic rays. We analyse the implications for supergravity models with universal boundary conditions at the grand unification scale. Together with low-energy observables one obtains a window of superparticle masses, which will soon be probed at the LHC, and a range of allowed reheating temperatures.