Abstract
The excess of events in the diphoton final state near 750 GeV observed byATLAS and CMS can be explained within the NMSSM near the R-symmetry limit. Bothscalars beyond the Standard Model Higgs boson have masses near 750 GeV, mix strongly,and share sizeable production cross sections in association with b-quarks as well as branching fractions into a pair of very light pseudoscalars. Pseudoscalars with a mass of ∼210 MeVdecay into collimated diphotons, whereas pseudoscalars with a mass of ∼ 500–550 MeV candecay either into collimated diphotons or into three π0resulting in collimated photon jets.Various such scenarios are discussed; the dominant constraints on the latter scenario originate from bounds on radiative Υ decays, but they allow for a signal cross section up to6.7 fb times the acceptance for collimated multiphotons to pass as a single photon.