Light Neutralinos in the NMSSM

TL;DR

This paper explores the parameter space of the NMSSM to identify very light neutralino dark matter candidates, highlighting the role of light Higgs particles in detection prospects and astrophysical signals.

Contribution

It demonstrates the existence of sub-15 GeV neutralino dark matter in the NMSSM using MCMC scans, emphasizing the importance of light Higgs states for detection.

Findings

Light neutralinos can be consistent with current constraints.

Light scalar Higgses enhance direct detection signals.

Resonant pseudoscalar exchanges affect gamma-ray yields.

Abstract

Next-to-Minimal Supersymmetric Standard Model neutralino dark matter candidates in the (1-15) GeV range are found with a Markov Chain Monte Carlo scanning code. A very light, singlet-like Higgs and/or CP-odd Higgs is needed in order to achieve such light masses. Light scalar Higgses can yield large direct detection cross sections, suitable for an account of the recent claims for signals. Neutralino annihilations via resonant light pseudoscalar Higgs exchanges can overproduce the indirect yield of gamma-rays from dwarf spheroidal galaxies. Hence, direct and indirect detection experiments probe different configurations of the NMSSM with a light neutralino DM candidate.