Gamma-ray line from radiative decay of gravitino dark matter

TL;DR

This paper investigates how gravitino dark matter with R-parity violation can produce a gamma-ray line consistent with Fermi-LAT observations, without conflicting with other gamma-ray and anti-proton data.

Contribution

It demonstrates that radiative decay of gravitino dark matter can generate observable gamma-ray lines with specific parameter ranges for sfermion masses and R-parity violating couplings.

Findings

Gamma-ray line can be explained by gravitino decay with appropriate parameters.

Branching ratio into monochromatic photons can be sufficiently large.

Model parameters are consistent with existing gamma-ray and anti-proton constraints.

Abstract

We study radiative decay of gravitino dark matter with trilinear R-parity violations. We show that the branching ratio of the decay of gravitino into monochromatic photon can be large enough to explain the observed gamma-ray line from the Galactic centre in the Fermi-LAT data without producing too much continuum gamma-ray and anti-proton flux. This scenario is realized when the mass of sfermions and the trilinear R-parity violating coupling are $O(1-10)$ TeV and $O(10^{-7}-10^{-6})$ respectively.