Measurement of the branching fractions for Ψ(2S)→e +e- and Ψ(2S)→μ+-
B Aubert, D Boutigny, JM Gaillard, A Hicheur et autres
We measure the branching fractions of the Ψ(2S) meson to the leptonic final states e+e- and μ+μ- relative to that for Ψ(2S)→J/Ψπ_. The method uses Ψ(2S) mesons produced in the decay of B mesons at the Y(45) resonance in a data sample …