Study of diphoton decays of the lightest scalar Higgs boson in the Next-to-Minimal Supersymmetric Standard Model

Abstract：

The CMS and ATLAS experiments at the LHC have announced the discovery of a Higgs boson with mass at approximately 125 GeV/ c ²in the search for the Standard Model Higgs boson via, notably, the γ γand ZZ to four leptons final states. Considering the recent results of the Higgs boson searches from the LHC, we study the lightest scalar Higgs boson h ₁in the Next-to-Minimal Supersymmetric Standard Model by restricting the next-to-lightest scalar Higgs boson h ₂to be the observed to the 125 GeV/ c ²state. We perform a scan over the relevant NMSSM parameter space that is favoured by low fine-tuning considerations. Moreover, we also take the experimental constraints from direct searches, B-physics observables, relic density, and anomalous magnetic moment of the muon measurements, as well as the theoretical considerations, into account in our specific scan. We find that the signal rate in the two-photon final state for the NMSSM Higgs boson h ₁with the mass range from about 80 GeV/ c ²to about 122 GeV/ c ²can be enhanced by a factor of up to 3.5 when the Higgs boson h ₂is required to be compatible with the excess from latest LHC results. This motivates the extension of the search at the LHC for the Higgs boson h ₁in the diphoton final state down to masses of 80 GeV/ c ², particularly with the upcoming proton-proton collision data to be taken at center-of-mass energies of 13-14 TeV.