Hunting a light CP-odd non-standard Higgs boson through its tauonic decay at a (Super) B factory

Several scenarios beyond the minimal extension of the Standard Model still allow light non-standard Higgs bosons evading LEP bounds. We examine the mixing between a light CP-odd Higgs boson and ηb states and its implications on a slight (but observable) lepton universality breaking in Upsilon decays to be measured at the percent level at a (Super) B factory.