Quark Seesaw, Vectorlike Fermions and Diphoton Excess

TL;DR

This paper proposes that a scalar field in quark seesaw left-right models with vectorlike fermions could explain the 750 GeV diphoton excess observed at the LHC, offering testable predictions for future data.

Contribution

It introduces a novel interpretation of the diphoton excess within quark seesaw models, connecting it to vectorlike fermions and the strong CP problem without axions.

Findings

Scalar field can produce the observed diphoton excess

Model predicts specific signatures for future LHC tests

Provides a new link between diphoton excess and strong CP problem

Abstract

We present a possible interpretation of the recent diphoton excess reported by the $\sqrt s=13$ TeV LHC data in quark seesaw left-right models with vectorlike fermions proposed to solve the strong $CP$ problem without the axion. The gauge singlet real scalar field responsible for the mass of the vectorlike fermions has the right production cross section and diphoton branching ratio to be identifiable with the reported excess at around 750 GeV diphoton invariant mass. Various ways to test this hypothesis as more data accumulates at the LHC are proposed.