Diphoton signal of the light Higgs boson in natural NMSSM

The natural Next-to-Minimal Supersymmetric Standard Model (nNMSSM) is featured by predicting one $CP$-even Higgs boson satisfying m_h₁120 GeV and Higgsinos lighter than about 300 GeV, and consequently, the cross section for dark matter (DM)-nucleon scattering in this scenario is usually quite large. We study the diphoton signal of the light Higgs boson in nNMSSM by considering the tight constraints from the latest LUX and PandaX-II experiments, and we conclude that the optimal value of the signal rate at 8 TeV LHC is greatly reduced in comparison with earlier predictions. For example, previous studies indicated that the rate may exceed 120 fb for m_h₁80 GeV, while it is at most 25 fb if the lightest neutralino in the scenario is fully responsible for the measured DM relic density. We also investigate the case of m_h₁98 GeV, which is hinted by the excesses of the large electron proton collider analysis on Zb̄b signal and the compact muon solenoid analysis on the diphoton signal. We conclude that nNMSSM can simultaneously explain the excesses at the 1σ level without violating any known constraints.