Interpreting 750 GeV diphoton resonance as degenerate Higgs bosons in NMSSM with vector-like particles

In this work, we explain the 750 GeV diphoton resonance in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) by introducing vector-like particles. Such an extension is well motivated from the top-down view since some grand unified theories usually predict the existence of singlet scalars and vector-like particles at weak scale. In our model, the 750 GeV resonance can be interpreted as two nearly degenerate singlet-like Higgs bosons (mh2 ≈ ma1 ≈ 750 GeV). Under the constraints from the LHC data and dark matter experiments, we scan the parameter space and find that such a model can successfully account for the 750 GeV diphoton excess. Besides, we find that the two 750 GeV Higgs bosons h2 and a1 can sizably decay to χ 0 1χ 0 1 invisibly. Therefore, search for the monojet events through the process gg → h2/a1(→ χ1χ1)j can further test our scenario at the future LHC.