Pair production of Higgs boson in NMSSM at the LHC with the next-to-lightest CP-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 h(2) is the SM-like Higgs boson h, whereas the lightest CP-even Higgs boson h(1) is dominantly singlet-like. We discuss the h(1)h(1), h(2)h(2), and h(1)h(2) 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 b (b) over bar and the other one decays to gamma gamma or tau(+)tau(- ) We find that, for m(h1) less than or similar to 62 GeV, the cross section of the gg -> h(1)h(1) process is relatively large and maximally reaches 5400 fb, and the production rate of the h(1)h(1) -> b (b) over bar tau(+)tau(- ) 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 -> h(2) -> h(1)h(1) and the relatively large branching ratio of h(1) -> b (b) over bar and h(1) -> tau(+)tau- . The cross sections of the pp -> h(2)h(2) and pp -> h(1)h(2 )production processes maximally reach 28 fb and 133 fb, respectively.