$\nu_R$ dark matter-philic Higgs for 3.5 keV X-ray signal

TL;DR

This paper proposes a new model for 7 keV right-handed neutrino dark matter, inspired by the 3.5 keV X-ray line, involving a special Higgs boson with a tiny vacuum expectation value to explain dark matter properties.

Contribution

Introduction of a dark matter-philic Higgs boson with a small VEV to generate suitable neutrino masses and explain the X-ray signal.

Findings

Dark matter-philic Higgs VEV ~ 0.17 GeV

Model consistent with 3.5 keV X-ray line

Suitable parameter space identified

Abstract

We suggest a new model of 7 keV right-handed neutrino dark matter inspired by a recent observation of 3.5 keV X-ray line signal in the XMM-Newton observatory. It is difficult to derive the tiny masses with a suitable left-right mixing of the neutrino in a framework of ordinary simple type-I seesaw mechanism. We introduce a new Higgs boson, a dark matter-philic Higgs boson, in which the smallness of its vacuum expectation value can be achieved. We investigate suitable parameter regions where the observed dark matter properties are satisfied. We find that the vacuum expectation value of dark matter-philic Higgs boson should be about 0.17 GeV.