Singlet extension of the MSSM as a solution to the small cosmological scale anomalies

TL;DR

This paper proposes that a general singlet extension of the MSSM can naturally produce self-interacting singlino dark matter to address small-scale cosmological anomalies, unlike the constrained NMSSM.

Contribution

It introduces a broader singlet extension framework that enables self-interacting dark matter, overcoming limitations of the NMSSM with Z3 symmetry.

Findings

General singlet extension can produce self-interacting singlino dark matter

NMSSM with Z3 symmetry cannot achieve the same due to parameter restrictions

Introduction of symmetric and antisymmetric viscosity cross sections for dark matter scattering

Abstract

In this work we show that the general singlet extension of the MSSM can naturally provide a self-interacting singlino dark matter to solve the small cosmological scale anomalies (a large Sommerfeld enhancement factor can also be obtained). However, we find that the NMSSM (the singlet extension of the MSSM with Z3 symmetry) cannot achieve this due to the restricted parameter space. In our analysis we introduce the concept of symmetric and antisymmetric viscosity cross sections to deal with the non-relativistic Majorana-fermion dark matter scattering.