1. Observation of electromagnetic Dalitz decays J/ψ→Pe+e-
- Author
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Ablikim, M, Achasov, MN, Ai, XC, Albayrak, O, Albrecht, M, Ambrose, DJ, An, FF, An, Q, Bai, JZ, Ferroli, R Baldini, Ban, Y, Bennett, JV, Bertani, M, Bian, JM, Boger, E, Bondarenko, O, Boyko, I, Braun, S, Briere, RA, Cai, H, Cai, X, Cakir, O, Calcaterra, A, Cao, GF, Cetin, SA, Chang, JF, Chelkov, G, Chen, G, Chen, HS, Chen, JC, Chen, ML, Chen, SJ, Chen, X, Chen, XR, Chen, YB, Cheng, HP, Chu, XK, Chu, YP, Cronin-Hennessy, D, Dai, HL, Dai, JP, Dedovich, D, Deng, ZY, Denig, A, Denysenko, I, Destefanis, M, Ding, WM, Ding, Y, Dong, C, Dong, J, Dong, LY, Dong, MY, Du, SX, Fan, JZ, Fang, J, Fang, SS, Fang, Y, Fava, L, Feng, CQ, Fu, CD, Fu, JL, Fuks, O, Gao, Q, Gao, Y, Geng, C, Goetzen, K, Gong, WX, Gradl, W, Greco, M, Gu, MH, Gu, YT, Guan, YH, Guo, AQ, Guo, LB, Guo, T, Guo, YP, Han, YL, Harris, FA, He, KL, He, M, He, ZY, Held, T, Heng, YK, Hou, ZL, Hu, C, Hu, HM, Hu, JF, Hu, T, Huang, GM, Huang, GS, Huang, HP, Huang, JS, Huang, L, Huang, XT, Huang, Y, Hussain, T, Ji, CS, Ji, Q, Ji, QP, and Ji, XB
- Subjects
Nuclear and Plasma Physics ,Particle and High Energy Physics ,Physical Sciences ,hep-ex ,Astronomical and Space Sciences ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Quantum Physics ,Nuclear & Particles Physics ,Mathematical physics ,Astronomical sciences ,Particle and high energy physics - Abstract
Based on a sample of (225.3 ± 2.8) × 106 J/ψ events collected with the BESIII detector, the electromagnetic Dalitz decays of J/ψ → Pe+e- (P = η'/η/π∗0) are studied. By reconstructing the pseudoscalar mesons in various decay modes, the decays J/ψ → η' e+e-, J/ψ → η e+e-, and J/ψ → π0 e+e- are observed for the first time. The branching fractions are determined to be B(J/ψ → η' e+e-) = (5.81 ± 0.16 ± 0.31) × 10-5, B(J/ψ → η e+e-) = (1.16 ± 0.07 ± 0.06) × 10-5, and B(J/ψ → π0 e+e-) = (7.56 ± 1.32 ±0.50) × 10-7, where the first errors are statistical and the second ones systematic.
- Published
- 2014