3.5 keV X-ray line and R-Parity Conserving Supersymmetry

Understand

We present some R-parity conserving supersymmetric models which can accommodate the 3.5 keV X-ray line reported in recent spectral studies of the Perseus galaxy cluster and the Andromeda galaxy.

• Within the Minimal Supersymmetric Standard Model (MSSM) framework, the dark matter (DM) gravitino (or the axino) with mass of around 7 keV decays into a massless neutralino (bino) and a photon with lifetime ~10^{28} sec.
• The massless bino contributes to the effective number of neutrino species N_eff and future data will test this prediction.
• In the context of NMSSM, we first consider scenarios where the bino is massless and the singlino mass is around 7 keV.