Is symmetry breaking of SU(5) theory responsible for the diphoton excess?

TL;DR

This paper proposes that the 750 GeV diphoton excess observed at the LHC can be explained by a scalar field from SU(5) symmetry breaking, involving specific scalar multiplets that influence its production and decay.

Contribution

It introduces a novel SU(5) symmetry breaking scalar that accounts for the diphoton excess, linking it to specific scalar multiplets and their role in fermion mass generation.

Findings

The scalar singlet can produce the diphoton excess via scalar multiplets.

The dominance of scalar multiplets affects fermion mass generation.

Testable diboson decay signatures are predicted.

Abstract

We advocate the possibility that the observed diphoton excess at 750 GeV at the LHC can be addressed by the scalar field that is a part of the SU(5) symmetry breaking sector. The field in question is the Standard Model singlet that resides in the adjoint representation that breaks SU(5) down to SU(3) x SU(2) x U(1). We also show that the required production and subsequent decay to two photons of this singlet can be induced by individual or combined contribution of two scalar multiplets $S_3$ and $R_2$ that transform as (3,3,-1/3) and (3,2,7/6) under SU(3) x SU(2) x U(1), respectively. The individual dominance of these multiplets is directly related to the issue of the charged fermion mass generation within the SU(5) framework and can be unambiguously tested through the diboson decay signatures of the Standard Model singlet field.