Oscillating Asymmetric Sneutrino Dark Matter from the Maximally $U(1)_L$ Supersymmetric Inverse Seesaw

TL;DR

This paper explores how a tiny mass splitting in supersymmetric inverse seesaw models affects sneutrino dark matter, highlighting the conditions under which asymmetric dark matter can be preserved despite oscillations.

Contribution

It analyzes the impact of small $U(1)_L$ breaking-induced mass splittings on sneutrino oscillations and identifies conditions favoring asymmetric dark matter stability.

Findings

Weak scale sneutrinos tolerate larger $ ext{delta}m extasciitilde 10^{-5}$ eV

Oscillation effects can spoil asymmetric dark matter if $ ext{delta}m$ is too large

Natural mechanisms for small $ ext{delta}m$ are discussed

Abstract

The inverse seesaw mechanism provides an attractive approach to generate small neutrino mass, which origins from a tiny $U(1)_L$ breaking. In this paper, we work in the supersymmetric version of this mechanism, where the singlet-like sneutrino could be an asymmetric dark matter (ADM) candidate in the maximally $U(1)_{L}$ symmetric limit. However, even a tiny $\delta m$, the mass splitting between sneutrino and anti-sneutrino as a result of the tiny $U(1)_{L}$ breaking effect, could lead to fast oscillation between sneutrino and anti-sneutrino and thus spoils the ADM scenario. We study the evolution of this oscillation and find that a weak scale sneutrino, which tolerates a relatively larger $\delta m\sim 10^{-5}$ eV, is strongly favored. We also investigate possible natural ways to realize that small $\delta m$ in the model.