130 GeV Fermi gamma-ray line from dark matter decay

TL;DR

The paper proposes a new dark matter decay model involving a scalar particle with a TeV-scale vacuum expectation value, which explains the 130 GeV gamma-ray line observed by Fermi-LAT, challenging conventional annihilation explanations.

Contribution

It introduces a novel decay mechanism for scalar dark matter via a dimension 6 operator suppressed by the GUT scale, providing a viable explanation for the gamma-ray line.

Findings

Decay of scalar dark matter explains the gamma-ray line

Model aligns with GUT-scale suppressed operators

Proposes a scalar dark matter with TeV-scale VEV

Abstract

The 130 GeV gamma-ray line based on tentative analyses on the Fermi-LAT data is hard to be understood with dark matter annihilation in the conventional framework of the MSSM. We point out that it can be nicely explained with two body decay of a scalar dark matter ($\tilde{\phi}_{\rm DM}\rightarrow\gamma\gamma$) by the dimension 6 operator suppressed with the mass of the grand unification scale ($\sim 10^{16}$ GeV), ${\cal L}\supset|\tilde{\phi}_{\rm DM}|^2F_{\mu\nu}F^{\mu\nu}/M_{\rm GUT}^2$, in which the scalar dark matter $\tilde{\phi}_{\rm DM}$ develops a TeV scale vacuum expectation value. We propose a viable model explaining the 130 GeV gamma-ray line.