Interpreting 750 GeV Diphoton Excess in Plain NMSSM

TL;DR

This paper proposes a NMSSM-based explanation for the 750 GeV diphoton excess through a cascade decay involving singlet-like scalars and higgsinos, aligning with LHC data at 13 TeV.

Contribution

It introduces a novel NMSSM decay chain model that accounts for the diphoton excess without conflicting with previous 8 TeV data.

Findings

Cascade decay of NMSSM Higgs bosons can explain the 750 GeV diphoton excess.

Model is consistent with both 13 TeV and 8 TeV LHC data.

Higgsino loops facilitate the decay of the singlet-like scalar into two photons.

Abstract

NMSSM has enough ingredients to explain the diphoton excess at 750 GeV: singlet-like (pseudo) scalar ($a$) $s$ and higgsinos as heavy vector-like fermions. We consider the production of the 750 GeV singlet-like pseudo scalar a from a decay of the doublet-like pseudo scalar $A$, and the subsequent decay of $a$ into two photons via higgsino loop. We demonstrate that this cascade decay of the NMSSM Higgs bosons can explain the diphoton excess in the 13 TeV data consistently with the absence of a significant excess in the 8 TeV data.