Updated constraints from radiative $\Upsilon$ decays on a light CP-odd Higgs

TL;DR

This paper reviews experimental bounds on radiative Upsilon decays to constrain the properties of a hypothetical light CP-odd Higgs boson, focusing on the mass range of 8-10 GeV, and discusses implications for new physics models.

Contribution

It provides updated constraints on a light CP-odd Higgs from radiative Upsilon decay data, considering mixing effects and small photon energy limits.

Findings

Constraints on pseudoscalar mass between 8-10 GeV

Limits on the branching ratio of Upsilon to gamma tau+ tau-

Implications for new physics models with light CP-odd Higgs

Abstract

The possible existence of a light CP-odd Higgs state in many new-physics models could lead to observable effects in the bottomonium sector. Experimental bounds on radiative $\Upsilon$ decays through such a pseudoscalar state and possible mixings with the $\eta_b^0$ states are reviewed. Combining these two effects, we set constraints on the properties of the CP-odd Higgs in the limit of small photon energy of $BR(\Upsilon\to\gamma\,\tau^+\tau^-)$, that is on the pseudoscalar mass-range $\sim8-10$GeV.