Testing Higgs boson scenarios in the phenomenological NMSSM

TL;DR

This paper performs a comprehensive Bayesian analysis of the phenomenological NMSSM to investigate the possibility of an additional light scalar Higgs boson near 125 GeV, using collider and dark matter data.

Contribution

It is the first to conduct global fits of a 26-parameter NMSSM using PolyChord, assessing the potential to distinguish scenarios with multiple Higgs bosons.

Findings

Data shows moderate support for an additional light scalar below W-boson mass.

Current constraints are insufficient for definitive conclusions on very light or near 125 GeV Higgs.

Further data needed for decisive discrimination between Higgs scenarios.

Abstract

There could be another scalar in nature quasi-degenerate with the observed one (h125). This is possible in models such as the Next-to-Minimal Supersymmetric Standard Model (NMSSM). The scenario(s) with a single Higgs boson can be compared to that with multiple ones, all near 125 GeV. In order to assess the extent to which the current set of collider, cold dark matter relic density and direct detection limits are capable of discriminating these scenarios, we perform, for the first-time, global fits of a weak-scale phenomenological NMSSM with 26 free parameters using the nested sampling implementation in PolyChord, a next-generation tool for Bayesian inference. The analyses indicate that the data used shows a moderate tendency for supporting the scenario with an additional scalar much lighter than h125 with mass distribution centred below the W-boson mass. More stringent constraints are, however, needed for decisive inference regarding an additional Higgs boson with mass much less than or near 125 GeV.