Pair production of Higgs boson in NMSSM at the LHC with the next-to-lightest C P-even Higgs boson being SM-like

The next-to-minimal supersymmetric standard model (NMSSM) more naturally accommodates a Higgs boson with a mass of approximately 125 GeV than the minimal supersymmetric standard model (MSSM). In this work, we assume that the next-to-lightest CP-even Higgs boson h₂ is the SM-like Higgs boson h, whereas the lightest CP-even Higgs boson h₁ is dominantly singlet-like. We discuss the h₁h₁, h₂h₂, and h₁h₂ pair production processes via gluon-gluon fusion at the LHC for an collision energy of 14 TeV, and we consider the cases in which one Higgs boson decays to bb and the other decays to γγ or τ⁺τ^-. We find that, for m_h1? 62 GeV, the cross section of the gg→h₁h₁ process is relatively large and maximally reaches 5400 fb, and the production rate of the h₁h₁→bbτ⁺τ^-final state can reach 1500 fb, which make the detection of this final state possible for future searches of an integrated luminosity of 300 and 3000 fb^-1. This is mainly due to the contributions from the resonant production process pp→h₂→h₁h₁ and the relatively large branching ratio of h₁→bb and h₁→τ⁺τ^-. The cross sections of the pp→h₂h₂ and pp→h₁h₂ production processes maximally reach 28 fb and 133 fb, respectively.