Updated constraints from radiative ${\rm Y}$ decays on a 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 ${\rm Y}$ 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 $BR({\rm Y}\to \gamma {\tau }^{+}{\tau }^{-})$, that is on the pseudoscalar mass-range $\sim 8-10$GeV.

Comments: 13 pages, 8 figures