χc1 and χc2 Resonance Parameters with the Decays χc1,c2→J/ψμ+μ−

The decays χc1→J/ψμ+μ− and χc2→J/ψμ+μ− are observed and used to study the resonance parameters of the χc1 and χc2 mesons. The masses of these states are measured to be m(χc1)=3510.71±0.04(stat)±0.09(syst)  MeV and m(χc2)=3556.10±0.06(stat)±0.11(syst)  MeV, where the knowledge of the momentum scale for charged particles dominates the systematic uncertainty. The momentum-scale uncertainties largely cancel in the mass difference m(χc2)−m(χc1)=45.39±0.07(stat)±0.03(syst)  MeV. The natural width of the χc2 meson is measured to be Γ(χc2)=2.10±0.20(stat)±0.02(syst)  MeV. These results are in good agreement with and have comparable precision to the current world averages.