Explaining the diphoton excess in Alternative Left-Right Symmetric Model

TL;DR

This paper explains the 750 GeV diphoton excess observed at the LHC using an $E_6$ motivated Alternative Left-Right Symmetric Model, linking it to flavor anomalies and high-scale leptogenesis, with scalar leptoquarks mediating production and decay.

Contribution

It introduces a novel explanation for the diphoton excess within the ALRSM framework, connecting it to flavor anomalies and leptogenesis, with detailed mechanisms involving scalar leptoquarks.

Findings

Gluon-gluon fusion via scalar leptoquarks explains the resonance production.

Loop contributions from $ ilde{h}^{(c)}$ and $ ilde{E}^{(c)}$ enhance diphoton decay.

Model successfully accounts for observed diphoton cross section.

Abstract

We propose a possible explanation of the recent diphoton excess reported by ATLAS and CMS collaborations, at around 750 GeV diphoton invariant mass, within the framework of $E_{6}$ motivated Alternative Left-Right Symmetric Model (ALRSM), which is capable of addressing the $B$ decay anomalies in the flavor sector, the $eejj$ and $e$ missing $p_{T}jj$ excesses reported by CMS in run 1 of LHC and has the feature of high scale leptogenesis. We find that gluon-gluon fusion can give the observed production rate of the 750 GeV resonance, $\tilde{n}$, through a loop of scalar leptoquarks ($\tilde{h}^{(c)}$) with mass below a few TeV range, while $\tilde{n}$ can subsequently decay into $\gamma\gamma$ final state via loops of $\tilde{h}^{(c)}$ and $\tilde{E}^{(c)}$. Interestingly, the $\tilde{E}^{(c)}$ loop can enhance the diphoton branching ratio significantly to successfully explain the observed cross section of the diphoton signal.