Search for Dimuon Decays of a Light Scalar in Radiative Transitions $\Upsilon\to\gamma A^0$

We report on a search for evidence of a light Higgs boson in the radiative decays of the narrow $\Upsilon$ resonances: $\Upsilon\to\gamma A^0$, $A^0\to\mu^+\mu^-$, using data collected by the {\it B{\footnotesize A}B{\footnotesize AR}} detector. Such an object appears in extensions of the Standard Model, where a light CP-odd Higgs boson naturally couples strongly to $b$-quarks.