Electroweak Vacuum Stability and Diphoton Excess at 750 GeV

Understand

Recently, both ATLAS and CMS collaborations at the CERN Large Hadron Collider (LHC) have announced their observations of an excess of diphoton events around the invariant mass of $750~{\rm GeV}$ with a local significance of $3.6\sigma$ and $2.6\sigma$, respectively.

• In this paper, we interpret the diphoton excess as the on-shell production of a real singlet scalar in the $pp \to S \to \gamma \gamma$ channel.
• To accommodate the observed production rate, we further introduce a vector-like fermion $F$, which is carrying both color and electric charges.
• The viable regions of model parameters are explored for this simple extension of the Standard Model (SM).