Radiative gravitino decays from R-parity violation

TL;DR

This paper investigates how radiative decay processes of gravitinos in R-violating supersymmetry can dominate over tree-level decays, with implications for dark matter and collider experiments.

Contribution

It provides a detailed calculation of gravitino decay widths and explores the phenomenological consequences of R-violating interactions involving the third generation.

Findings

Radiative decay $ ilde{G} o \gamma u$ can dominate over tree-level decays.

Slow-decaying gravitinos are viable dark matter candidates.

Branching ratios depend on the hierarchy of R-violating operators.

Abstract

We study radiative gravitino decay within the framework of R-violating supersymmetry. For trilinear R-violating couplings that involve the third generation of fermions, or for light gravitinos, we find that the radiative loop-decay $\tilde{G} \to \gamma \nu$ dominates over the tree-level ones for a wide set of parameters. We calculate the gravitino decay width and study its implications for cosmology and collider physics. Slow-decaying gravitinos are good dark matter candidates, for a range of parameters that would also predict observable R-violating signatures in colliders. In general the branching ratios are very dependent on the relative hierarchies of R-violating operators, and may provide relevant information on the flavour structure of the underlying fundamental theory.