A Naturally Light Sterile neutrino in an Asymmetric Dark Matter Model

TL;DR

This paper presents a model linking asymmetric dark matter with a 3+1 neutrino spectrum, where a naturally light sterile neutrino arises from radiative mechanisms and gravitational effects, fitting observed neutrino oscillation data.

Contribution

It introduces a novel asymmetric mirror dark matter model that naturally produces a light sterile neutrino through radiative inverse seesaw and gravitational effects, with specific mixing mechanisms.

Findings

The model predicts a 3+1 neutrino spectrum with a light sterile neutrino.

Active neutrino masses and mixings are generated radiatively, matching experimental data.

The sterile neutrino mass is primarily from gravitationally induced operators.

Abstract

A recently proposed asymmetric mirror dark matter model where the mirror sector is connected with the visible one by a right handed neutrino portal, is shown to lead naturally to a 3+1 active-sterile neutrino spectrum, if the portal consists only of two right handed neutrinos. At the tree level the model has four massless neutrino states, three active and one sterile. The active neutrinos pick up tiny masses via the minimal radiative inverse seesaw mechanism at the one loop level. The loop effects also generate the large solar and atmospheric mixings, as well as the observed reactor mixing for certain range of parameters of the model. The dominant contribution to the sterile neutrino mass ($\sim$ eV) arises from the gravitationally induced dimension-5 operators. Generating active-sterile mixing requires a two Higgs doublet extension of SM and a small mixing between the ordinary and mirror Higgs fields, which occurs naturally in mirror models.