Enhanced Higgs associated production with a top quark pair in the NMSSM with light singlets

TL;DR

This paper explores how the NMSSM with light singlets can enhance Higgs production with top quarks, aligning with experimental data and potentially explaining LEP2 excesses, while maintaining perturbative consistency.

Contribution

It demonstrates a perturbatively consistent NMSSM scenario with light singlets that enhances Higgs-top associated production and explains LEP2 excesses.

Findings

Enhanced Higgs-top associated production in NMSSM with light singlets.

Scenario consistent with perturbative unification up to GUT scale.

Potential explanation for LEP2 Higgs search excesses.

Abstract

Precision measurements of the 125 GeV Higgs resonance recently discovered at the LHC have determined that its properties are similar to the ones of the Standard Model (SM) Higgs boson. However, the current uncertainties in the determination of the Higgs boson couplings leave room for significant deviations from the SM expectations. In fact, if one assumes no correlation between the top-quark and gluon couplings to the Higgs, the current global fit to the Higgs data lead to central values of the Higgs couplings to the bottom-quark and the top-quark that are about 2 $\sigma$ away from the SM predictions. In a previous work, we showed that such a scenario could be realized in the Next to Minimal Supersymmetric extension of the SM (NMSSM), for heavy singlets and light MSSM-like Higgs bosons and scalar top quarks, but for couplings that ruined the perturbative consistency of the theory up to the GUT scale. In this work we show that a perturbative consistent scenario, for somewhat heavier stops, may be obtained in the presence of light singlets. An interesting bonus of this scenario is the possibility of explaining an excess of events observed in CP-even Higgs searches at LEP2.