7 keV Sterile neutrino dark matter in $U(1)_R-$ lepton number model

TL;DR

This paper explores a supersymmetric $U(1)_R$-lepton number model that naturally produces a keV sterile neutrino as warm dark matter, explaining recent X-ray signals and neutrino properties.

Contribution

It introduces a novel supersymmetric model that generates a keV sterile neutrino dark matter candidate with negligible active-sterile mixing and accounts for neutrino masses and Higgs mass.

Findings

Sterile neutrino can explain the 3.5 keV X-ray line.

Model accommodates a 125 GeV Higgs boson.

Light gravitino has significant cosmological implications.

Abstract

We study the phenomenology of a keV sterile neutrino in a supersymmetric model with $U(1)_R-$ lepton number in the light of a very recent observation of an X-ray line signal at around 3.5 keV, detected in the X-ray spectra of Andromeda galaxy and various galaxy clusters including the Perseus galaxy cluster. This model not only provides a small tree level mass to one of the active neutrinos but also renders a suitable warm dark matter candidate in the form of a sterile neutrino with negligible active-sterile mixing. Light neutrino masses and mixing can be explained once one-loop radiative corrections are taken into account. The scalar sector of this model can accommodate a Higgs boson with a mass of $\sim$ 125 GeV. In this model gravitino is the lightest supersymmetric particle (LSP) and we also study the cosmological implications of this light gravitino with mass $\sim \mathcal O$(GeV).