Fingerprinting the presence of extra scalars in the $h \to Vff'$ forward-backward asymmetry

TL;DR

This paper investigates how the Aligned two-Higgs Doublet Model can alter the forward-backward asymmetry in Higgs decays, potentially revealing new physics and CP-violation sources at future colliders.

Contribution

It demonstrates that the Aligned two-Higgs Doublet Model can significantly modify the Standard Model predictions for the forward-backward asymmetry in Higgs decays, highlighting potential experimental signatures.

Findings

Deviations from Standard Model predictions are possible in a large parameter space.

Additional CP-violation sources can enhance asymmetry signals.

Potential to observe new physics at the High Luminosity LHC or future Higgs factories.

Abstract

In this work we analyse the forward-backward asymmetry of the $h\to Vff'$ decay in the Aligned two-Higgs Doublet Model. The Standard Model prediction for this asymmetry for $V=W$ is small, as it suffers from Yukawa suppression and is absent for $V=Z$. This does not necessarily have to hold true in the Aligned model where these contributions can in principle be re-enhanced through the independent alignment factors $\varsigma_f$. In this analysis we conclude that, due to the additional contributions corresponding to the Aligned two-Higgs Doublet Model together with extra sources of CP-violation for the $V=Z$ channel, the Standard Model predictions can be significantly modified in a great region of the parameter space. These deviations, that could be potentially measured at the High Luminosity LHC or future Higgs factories, would be a clear signal of new physics, and would shed new light on the possible extensions of the Standard Model and new sources of CP-violation.