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.
Aaij, R., Adeva, B., Adinolfi, M., Ajaltouni, Z., Akar, S., Albrecht, J., et al. (2017). χc1 and χc2 Resonance Parameters with the Decays χc1,c2 →j /ψμ+μ-. PHYSICAL REVIEW LETTERS, 119(22) [10.1103/PhysRevLett.119.221801].
χc1 and χc2 Resonance Parameters with the Decays χc1,c2 →j /ψμ+μ-
Belloli, N.;Borsato, M.;Calvi, M.;Carniti, P.;Cassina, L.;Fazzini, D.;GarcÃa Pardiñas, J.;Gotti, C.
;Grillo, L.;Martinelli, M.;Matteuzzi, C.;Petruzzo, M.;
2017
Abstract
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.
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