Experimental constraints on nMSSM and implications on its phenomenology

TL;DR

This paper analyzes experimental constraints on the nMSSM, revealing tight parameter bounds, the significance of light A_1 in dark matter annihilation, and altered Higgs decay modes that impact phenomenology.

Contribution

It provides the first comprehensive analysis of experimental constraints on the nMSSM and explores implications for dark matter and Higgs phenomenology.

Findings

Neutralino mass constrained to 1-37 GeV.

Light A_1 significantly influences dark matter annihilation.

Higgs may predominantly decay invisibly or into A_1 pairs.

Abstract

We examine various direct and indirect experimental constraints on the nearly minimal supersymmetric standard model (nMSSM) and obtain the following observations: (i) Current experiments stringently constrain the parameter space, setting a range of 1-37 GeV for the lightest neutralino (LSP), 30-140 GeV (1-250 GeV) for the lightest CP-even (CP-odd) Higgs boson, and 1.5-10 for \tan\beta; (ii) To account for the dark matter relic density, besides the s-channel exchange of a Z-boson, the s-channel exchange of a light A_1 (the lightest CP-odd Higgs boson) can also play an important role in LSP annihilation. Compared with the Z-exchange annihilation channel, the A_1 exchange channel is more favored by muon g-2 data and allows much broader regions for the parameters; (iii) In a large part of the allowed parameter space the SM-like Higgs boson may dominantly decay to LSP pair or A_1 pair and the conventional visible decays (e.g. into bottom quarks) are severely suppressed.