Common Origin of $3.55$ keV X-ray line and Gauge Coupling Unification with Left-Right Dark Matter

Understand

We present a minimal left-right dark matter framework that can simultaneously explain the recently observed 3.55 keV X-ray line from several galaxy clusters and gauge coupling unification at high energy scale.

• Adopting a minimal dark matter strategy, we consider both left and right handed triplet fermionic dark matter candidates which are stable by virtue of a remnant $\mathcal{Z}_2\simeq (-1)^{B-L}$ symmetry arising after the spontaneous symmetry breaking of left-right gauge symmetry to that of the standard model.
• A scalar bitriplet field is incorporated whose first role is to allow radiative decay of right handed triplet dark matter into the left handed one and a photon with energy 3.55 keV.
• The other role this bitriplet field at TeV scale plays is to assist in achieving gauge coupling unification at a high energy scale within a non-supersymmetric $SO(10)$ model while keeping the scale of left-right gauge symmetry around the TeV corner.