An improved limit for Γ e e of X ( 3872 ) and Γ e e measurement of ψ ( 3686 )

• Published in: Physics letters. B 2015-10, Vol.749 (C), p.414-420
• Main Authors: Ablikim, M., Achasov, M.N., Ai, X.C., Albayrak, O., Albrecht, M., Ambrose, D.J., Amoroso, A., An, F.F., An, Q., Bai, J.Z., Baldini Ferroli, R., Ban, Y., Bennett, D.W., Bennett, J.V., Bertani, M., Bettoni, D., Bian, J.M., Bianchi, F., Boger, E., Bondarenko, O., Boyko, I., Briere, R.A., Cai, H., Cai, X., Cakir, O., Calcaterra, A., Cao, G.F., Cetin, S.A., Chang, J.F., Chelkov, G., Chen, G., Chen, H.S., Chen, H.Y., Chen, J.C., Chen, M.L., Chen, S.J., Chen, X., Chen, X.R., Chen, Y.B., Cheng, H.P., Chu, X.K., Cibinetto, G., Cronin-Hennessy, D., Dai, H.L., Dai, J.P., Dbeyssi, A., Dedovich, D., Deng, Z.Y., Denig, A., Denysenko, I., Destefanis, M., De Mori, F., Ding, Y., Dong, C., Dong, J., Dong, L.Y., Dong, M.Y., Du, S.X., Duan, P.F., Fan, J.Z., Fang, J., Fang, S.S., Fang, X., Fang, Y., Fava, L., Feldbauer, F., Felici, G., Feng, C.Q., Fioravanti, E., Fritsch, M., Fu, C.D., Gao, Q., Gao, X.Y., Gao, Y., Gao, Z., Garzia, I., Geng, C., Goetzen, K., Gong, W.X., Gradl, W., Greco, M., Gu, M.H., Gu, Y.T., Guan, Y.H., Guo, A.Q., Guo, L.B., Guo, Y., Guo, Y.P., Haddadi, Z., Hafner, A., Han, S., Han, Y.L., Hao, X.Q., Harris, F.A., He, K.L., He, Z.Y., Held, T., Heng, Y.K., Hou, Z.L., Hu, C.
• Format: Article
• Language: English
• Subjects: BESIII; charmonium spectroscopy; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; X; Γee; ψ
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2015.08.013

In this study, using the data sets taken at center-of-mass energies above 4 GeV by the BESIII detector at the BEPCII storage ring, we search for the reaction e⁺e⁻ → γISRX(3872) → γISRπ+π-J/ψ via the Initial State Radiation technique. The production of a resonance with quantum numbers JPC=1++ such as the X(3872) via single photon e⁺e⁻ annihilation is forbidden, but is allowed by a next-to-leading order box diagram.