Bottomonium Spectroscopy with Mixing ofηbStates and a LightCP-Odd Higgs Boson

Abstract

The mass of the ${\ensuremath{\eta}}_{b}(1S)$, measured recently by the BABAR Collaboration, is significantly lower than expected from QCD predictions for the $\ensuremath{\Upsilon}(1S)\mathrm{\text{\ensuremath{-}}}{\ensuremath{\eta}}_{b}(1S)$ hyperfine splitting. We suggest that the observed ${\ensuremath{\eta}}_{b}(1S)$ mass is shifted downwards due to a mixing with a $CP$-odd Higgs boson $A$ with a mass ${m}_{A}$ in the range 9.4--10.5 GeV compatible with LEP, CLEO, and BABAR constraints. We determine the resulting predictions for the spectrum of the ${\ensuremath{\eta}}_{b}(nS)\mathrm{\text{\ensuremath{-}}}A$ system and the branching ratios into ${\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ as functions of ${m}_{A}$.