Exploring the Higgs Sector of a Most Natural NMSSM and its Prediction on Higgs Pair Production at the LHC

TL;DR

This paper investigates the { lambda}-SUSY model, a natural version of the NMSSM, revealing significant enhancements in Higgs self-couplings and pair production rates at the LHC, which are not achievable in minimal models.

Contribution

It performs a parameter space scan of { lambda}-SUSY considering experimental constraints and identifies unique Higgs features and the importance of naturalness in this model.

Findings

Triple Higgs self coupling can be over 10 times the SM prediction.

Higgs pair production at the LHC can be two orders of magnitude larger than in the SM.

Naturalness constrains the parameter space and improves fit to experimental data.

Abstract

As a most natural realization of the Next-to Minimal Supersymmetry Standard Model (NMSSM), {\lambda}-SUSY is parameterized by a large {\lambda} around one and a low tan$\beta$ below 10. In this work, we first scan the parameter space of {\lambda}-SUSY by considering various experimental constraints, including the limitation from the Higgs data updated by the ATLAS and CMS collaborations in the summer of 2014, then we study the properties of the Higgs bosons. We get two characteristic features of {\lambda}-SUSY in experimentally allowed parameter space. One is the triple self coupling of the SM-like Higgs boson may get enhanced by a factor over 10 in comparison with its SM prediction. The other is the pair production of the SM-like Higgs boson at the LHC may be two orders larger than its SM prediction. All these features seems to be unachievable in the Minimal Supersymmetric Standard Model and in the NMSSM with a low {\lambda}. Moreover, we also find that naturalness plays an important role in selecting the parameter space of {\lambda}-SUSY, and that the Higgs $\chi^2$ obtained with the latest data is usually significantly smaller than before due to the more consistency of the two collaboration measurements.