  In this work we examine the possible existence of new physics beyond the
standard model which could modify the branching fractions of the leptonic
(mainly tauonic) decays of bottomonium vector resonances below the $B\bar{B}$
threshold. The decay width is factorized as the product of two pieces: a) the
probability of an intermediate pseudoscalar color-singlet $b\bar{b}$ state
(coupling to the dominant Fock state of the Upsilon via a magnetic dipole
transition) and a soft (undetected) photon; b) the annihilation width of the
$b\bar{b}$ pair into two leptons, mediated by a non-standard CP-odd Higgs boson
of mass about 10 GeV, introducing a quadratic dependence on the lepton mass in
the partial width. The process would be unwittingly ascribed to the $\Upsilon$
leptonic channel thereby (slightly) breaking lepton universality. A possible
mixing of the pseudoscalar Higgs and bottomonium resonances is also considered.
Finally, several experimental signatures to check out the validity of the
conjecture are discussed.
