Supersymmetric mass spectra for gravitino dark matter with a high reheating temperature

TL;DR

This paper explores supersymmetric models with gravitino dark matter that accommodate high reheating temperatures, identifying a parameter space with nearly degenerate gluinos and neutralinos, and proposes monojet plus missing energy as a key LHC signature.

Contribution

It identifies a viable parameter space in supersymmetric models with gravitino dark matter that satisfies cosmological constraints and predicts distinctive collider signatures.

Findings

Gluino and neutralinos are nearly degenerate in the viable models.

High reheating temperatures compatible with leptogenesis are achievable.

Monojet plus missing energy is the main LHC discovery channel.

Abstract

Supersymmetric theories with gravitino dark matter generally do not allow the high reheating temperature required by thermal leptogenesis without running afoul of relic abundance or big bang nucleosynthesis constraints. We report on a successful search for parameter space that does satisfy these requirements. The main implication is the near degeneracy of the gluino with the other neutralinos in the spectrum. The leading discovery channel at the LHC for this scenario is through monojet plus missing energy events.