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

TL;DR

This paper proposes a minimal left-right dark matter model that explains the 3.55 keV X-ray line, achieves gauge coupling unification, and predicts testable collider signatures, all within a non-supersymmetric $SO(10)$ framework.

Contribution

It introduces a novel minimal left-right dark matter model with a scalar bitriplet that explains the X-ray line and unifies gauge couplings at high energy, while addressing neutrino masses and collider signals.

Findings

Explains the 3.55 keV X-ray line via dark matter decay.

Achieves gauge coupling unification at high scale.

Predicts collider signatures like diboson and dilepton excesses.

Abstract

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. Apart from solving the neutrino mass problem and giving verifiable new contributions to neutrinoless double beta decay and charged lepton flavour violation, the model with TeV scale gauge bosons can also give rise to interesting collider signatures like diboson excess, dilepton plus two jets excess reported recently in the large hadron collider data.