Constraining wrong-sign $hbb$ couplings with $h \rightarrow \Upsilon \gamma$

TL;DR

This paper investigates how the rare decay $h ightarrow u b3$ can be used to constrain the possibility of a wrong-sign $hbb$ coupling in two Higgs doublet models, which is otherwise allowed by current limits.

Contribution

It demonstrates that the decay $h ightarrow u b3$ can effectively limit wrong-sign $hbb$ couplings in models beyond the Standard Model.

Findings

$h ightarrow u b3$ decay rate is sensitive to $hbb$ coupling sign.

Current experimental limits can exclude certain wrong-sign scenarios.

The decay provides a new probe for Higgs coupling structure.

Abstract

The rare decay $h \rightarrow \Upsilon \gamma$ has a very small rate in the Standard Model, due to a strong cancellation between the direct and indirect diagrams. Models with a changed $hbb$ coupling can thus lead to a great increase in this decay. Current limits on two Higgs doublet models still allow for the possibility that the $hbb$ coupling might have a sign opposite to the Standard Model; the so-called "wrong-sign". We show how $h \rightarrow \Upsilon \gamma$ can be used to put limits on the wrong-sign solutions.