Fingerprinting the presence of extra scalars in the $h\to Vf{f}^{\prime }$ forward-backward asymmetry

Abstract

In this work we analyse the forward-backward asymmetry of the $h\to Vf{f}^{\prime }$ 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.

Comments: 25 pages, 7 figures. Minor changes made, references updated, some parts of the calculation have been moved to appendices. Matches version to be published in JHEP