Recent LHC data suggest an excess in the Higgs decay channels into $\gamma \gamma$ and $ZZ$ at $\sim 125\mathrm{GeV}$. The current excess in the diphoton channel is twice that expected from a standard model (SM) Higgs boson; while this may well change with more statistics, it is interesting to consider the implications should the result persist. Here, we assess whether the next-to-minimal supersymmetric standard model with a neutralino dark matter candidate could explain this excess when astrophysical constraints (e.g., no overproduction of gamma rays and radio emission in the galaxy, no anomalous excess in the dark matter direct detection experiments, and no dark matter overabundance) are imposed on the neutralino. This enables us to disregard unphysical regions of the parameter space even though the Higgs signal is compatible with the observed excess. The result of our analysis is that there are configurations of the parameter space that can explain the signal strength reported by the ATLAS and CMS Collaborations for a Higgs mass within the required range. Should the observed signal strength finally be compatible with SM expectations, it would be difficult to distinguish between the discovery of SM Higgs boson and a SM-like Higgs boson from the next-to-minimal supersymmetric standard model, unless one performs dedicated searches of very light Higgs bosons and possibly investigates peculiar signatures of supersymmetric particles. We also propose a new $\mathrm{\text{jets}}+\mathrm{\text{missing}}$ $E_T$ signal for the case where the lightest supersymmetric particle is a singlino-like neutralino.

• Received 10 April 2012

DOI:https://doi.org/10.1103/PhysRevD.86.035023