Two-Higgs-doublet model with a color-triplet scalar: a joint explanation for top quark forward-backward asymmetry and Higgs decay to diphoton

TL;DR

This paper proposes a two-Higgs-doublet model with a color-triplet scalar that can simultaneously explain the top quark forward-backward asymmetry and the Higgs to diphoton decay enhancement, predicting a unique correlation with the Zγ decay.

Contribution

It introduces a novel two-Higgs-doublet model with a color-triplet scalar that accounts for multiple anomalies and predicts distinctive Higgs decay correlations.

Findings

Model explains both anomalies at 1σ level.

Predicts suppressed Zγ decay and enhanced diphoton decay.

Provides a testable signature for future LHC runs.

Abstract

The excess of top quark forward-backward asymmetry ($A^t_{FB}$) reported by the Tevatron and the enhancement of the Higgs decay to diphoton observed by the LHC may point to a same origin of new physics. In this note we examined such anomalies in the two-Higgs-doublet model with a color-triplet scalar. We found that under current experimental constraints this model can simultaneously explain both anomalies at $1\sigma$ level. Also, we examined the Higgs decay $h\to Z\gamma$ and displayed its correlation with $h\to \gamma\gamma$. We found that unlike other models, this model predicts a special correlation between $h\to Z\gamma$ and $h\to \gamma\gamma$, i.e., the $Z\gamma$ rate is highly suppressed while the $\gamma\gamma$ rate is enhanced. This behavior may help to distinguish this model in the future high luminosity run of the LHC.