The Diphoton Excess Inspired Electroweak Baryogenesis

Abstract

A resonance in the diphoton channel with invariant mass $m_{\gamma \gamma} = 750$ GeV was claimed by the ATLAS and CMS collaborations at the run-2 LHC with $\sqrt{s}=13$ TeV. In this paper, we explain this diphoton excess as a pseudo-scalar singlet, which is produced at the LHC through gluon fusion with exotic scalar quarks running in the loop. We point out the scalar singlet might trigger a two-step electroweak phase transition, which can be strongly first oder. By assuming there are CP violations associated with interactions of the scalar quarks, the model is found to be able to generate adequate baryon asymmetry of the Universe through the electroweak baryogenesis mechanism. Constraints on the model are studied.