Zusammenfassung
We calculated the quasi exclusive leptonic decay width of Upsilon to NLO in
QED. The large logarithms are resummed too. Then we get R\_tau
mu=GammaUpsilon ->tau+tau-/GammaUpsilon -> mu+mu- at the precision level
of 0.1\% within Standard Model. Compared with the Babar's data R\_tau
mu=1.009+-0.01+-0.024, we find that Standard Model prediction is not
consistent with the experiment date in the error bar. The discrepancy is about
2\% or more. So leptonic decay of Upsilon may be a possible evidence of New
Physics. We also consider the impact of R\_tau mu from light Higgs h and
pseudoscalar Higgs A0 within New Physics Model.
Nutzer