We have studied the process e+e -→μ+μ-γ at a center-of-mass energy near the γ(4S) resonance for a μ+μ- invariant mass range near the J/Ψ mass and measured the cross section σ(e+e-→J/Ψ γt →μ +μ-γ). The data set, corresponding to an integrated luminosity of 88.4 fb-1, was collected using the BABAR detector at the SLAC PEP-II collider. From the measured cross section we extract the product Γ(J/Ψ→e+e-)B(J/ Ψ→μ+μ-) = 0.330±0.008±0.007 keV. Using the world averages for B(J/Ψ →μ+μ - and B(J/Ψ→e+e-), we derive the J/Ψ electronic and total widths: Γ(J/Ψ→e+e -) = 5.61 ±0.20 keV and Γ = 94.7 ± 4.4 keV.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics