Observation of the Dalitz Decay $η' \to γe^+e^-$
Creators: name: Ablikim, M.
name: Achasov, M. N.
name: Ai, X. C.
name: Albayrak, O.
name: Albrecht, M.
name: Ambrose, D. J.
name: Amoroso, A.
name: An, F. F.
name: An, Q.
name: Bai, J. Z.
name: Ferroli, R. Baldini
name: Ban, Y.
name: Bennett, D. W.
name: Bennett, J. V.
name: Bertani, M.
name: Bettoni, D.
name: Bian, J. M.
name: Bianchi, F.
name: Boger, E.
name: Bondarenko, O.
name: Boyko, I.
name: Briere, R. A.
name: Cai, H.
name: Cai, X.
name: Cakir, O.
name: Calcaterra, A.
name: Cao, G. F.
name: Cetin, S. A.
name: Chang, J. F.
name: Chelkov, G.
name: Chen, G.
name: Chen, H. S.
name: Chen, H. Y.
name: Chen, J. C.
name: Chen, M. L.
name: Chen, S. J.
name: Chen, X.
name: Chen, X. R.
name: Chen, Y. B.
name: Cheng, H. P.
name: Chu, X. K.
name: Cibinetto, G.
name: Cronin-Hennessy, D.
name: Dai, H. L.
name: Dai, J. P.
name: Dbeyssi, A.
name: Dedovich, D.
name: Deng, Z. Y.
name: Denig, A.
name: Denysenko, I.
name: Destefanis, M.
name: De Mori, F.
name: Ding, Y.
name: Dong, C.
name: Dong, J.
name: Dong, L. Y.
name: Dong, M. Y.
name: Du, S. X.
name: Duan, P. F.
name: Fan, J. Z.
name: Fang, J.
name: Fang, S. S.
name: Fang, X.
name: Fang, Y.
name: Fava, L.
name: Feldbauer, F.
name: Felici, G.
name: Feng, C. Q.
name: Fioravanti, E.
name: Fritsch, M.
name: Fu, C. D.
name: Gao, Q.
name: Gao, X. Y.
name: Gao, Y.
name: Gao, Z.
name: Garzia, I.
name: Geng, C.
name: Goetzen, K.
name: Gong, W. X.
name: Gradl, W.
name: Greco, M.
name: Gu, M. H.
name: Gu, Y. T.
name: Guan, Y. H.
name: Guo, A. Q.
name: Guo, L. B.
name: Guo, Y.
name: Guo, Y. P.
name: Haddadi, Z.
name: Hafner, A.
name: Han, S.
name: Han, Y. L.
name: Hao, X. Q.
name: Harris, F. A.
name: He, K. L.
name: He, Z. Y.
name: Held, T.
name: Heng, Y. K.
name: Hou, Z. L.
name: Hu, C.
name: Hu, H. M.
name: Hu, J. F.
name: Hu, T.
name: Hu, Y.
name: Huang, G. M.
name: Huang, G. S.
name: Huang, H. P.
name: Huang, J. S.
name: Huang, X. T.
name: Huang, Y.
name: Hussain, T.
name: Ji, Q.
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name: Ji, X. B.
name: Ji, X. L.
name: Jiang, L. L.
name: Jiang, L. W.
name: Jiang, X. S.
name: Jiao, J. B.
name: Jiao, Z.
name: Jin, D. P.
name: Jin, S.
name: Johansson, T.
name: Julin, A.
name: Kalantar-Nayestanaki, N.
name: Kang, X. L.
name: Kang, X. S.
name: Kavatsyuk, M.
name: Ke, B. C.
name: Kliemt, R.
name: Kloss, B.
name: Kolcu, O. B.
name: Kopf, B.
name: Kornicer, M.
name: Kühn, W.
name: Kupsc, A.
name: Lai, W.
name: Lange, J. S.
name: Lara, M.
name: Larin, P.
name: Leng, C.
name: Li, C. H.
name: Li, Cheng
name: Li, D. M.
name: Li, F.
name: Li, G.
name: Li, H. B.
name: Li, J. C.
name: Li, Jin
name: Li, K.
name: Li, K.
name: Li, Lei
name: Li, P. R.
name: Li, T.
name: Li, W. D.
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name: Liang, H.
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name: Liao, G. R.
name: Lin, D. X.
name: Liu, B. J.
name: Liu, C. X.
name: Liu, F. H.
name: Liu, Fang
name: Liu, Feng
name: Liu, H. B.
name: Liu, H. H.
name: Liu, H. H.
name: Liu, H. M.
name: Liu, J.
name: Liu, J. P.
name: Liu, J. Y.
name: Liu, K.
name: Liu, K. Y.
name: Liu, L. D.
name: Liu, P. L.
name: Liu, Q.
name: Liu, S. B.
name: Liu, X.
name: Liu, X. X.
name: Liu, Y. B.
name: Liu, Z. A.
name: Liu, Zhiqiang
name: Liu, Zhiqing
name: Loehner, H.
name: Lou, X. C.
name: Lu, H. J.
name: Lu, J. G.
name: Lu, R. Q.
name: Lu, Y.
name: Lu, Y. P.
name: Luo, C. L.
name: Luo, M. X.
name: Luo, T.
name: Luo, X. L.
name: Lv, M.
name: Lyu, X. R.
name: Ma, F. C.
name: Ma, H. L.
name: Ma, L. L.
name: Ma, Q. M.
name: Ma, S.
name: Ma, T.
name: Ma, X. N.
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name: Maas, F. E.
name: Maggiora, M.
name: Malik, Q. A.
name: Mao, Y. J.
name: Mao, Z. P.
name: Marcello, S.
name: Messchendorp, J. G.
name: Min, J.
name: Min, T. J.
name: Mitchell, R. E.
name: Mo, X. H.
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name: Morales, C. Morales
name: Moriya, K.
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name: Peng, H. P.
name: Peters, K.
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name: Ping, J. L.
name: Ping, R. G.
name: Poling, R.
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name: Qi, M.
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name: Qin, X. S.
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name: Qiu, J. F.
name: Rashid, K. H.
name: Redmer, C. F.
name: Ren, H. L.
name: Ripka, M.
name: Rong, G.
name: Ruan, X. D.
name: Santoro, V.
name: Sarantsev, A.
name: Savrié, M.
name: Schoenning, K.
name: Schumann, S.
name: Shan, W.
name: Shao, M.
name: Shen, C. P.
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name: Sheng, H. Y.
name: Song, W. M.
name: Song, X. Y.
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name: Spataro, S.
name: Sun, G. X.
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name: Tapan, I.
name: Thorndike, E. H.
name: Tiemens, M.
name: Toth, D.
name: Ullrich, M.
name: Uman, I.
name: Varner, G. S.
name: Wang, B.
name: Wang, B. L.
name: Wang, D.
name: Wang, D. Y.
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name: Wang, L. L.
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name: Weber, T.
name: Wei, D. H.
name: Wei, J. B.
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name: Wen, S. P.
name: Wiedner, U.
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name: Zafar, A. A.
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name: Zeng, Y.
name: Zhang, B. X.
name: Zhang, B. Y.
name: Zhang, C.
name: Zhang, C. C.
name: Zhang, D. H.
name: Zhang, H. H.
name: Zhang, H. Y.
name: Zhang, J. J.
name: Zhang, J. L.
name: Zhang, J. Q.
name: Zhang, J. W.
name: Zhang, J. Y.
name: Zhang, J. Z.
name: Zhang, K.
name: Zhang, L.
name: Zhang, S. H.
name: Zhang, X. Y.
name: Zhang, Y.
name: Zhang, Y. H.
name: Zhang, Y. T.
name: Zhang, Z. H.
name: Zhang, Z. P.
name: Zhang, Z. Y.
name: Zhao, G.
name: Zhao, J. W.
name: Zhao, J. Y.
name: Zhao, J. Z.
name: Zhao, Lei
name: Zhao, Ling
name: Zhao, M. G.
name: Zhao, Q.
name: Zhao, Q. W.
name: Zhao, S. J.
name: Zhao, T. C.
name: Zhao, Y. B.
name: Zhao, Z. G.
name: Zhemchugov, A.
name: Zheng, B.
name: Zheng, J. P.
name: Zheng, W. J.
name: Zheng, Y. H.
name: Zhong, B.
name: Zhou, L.
name: Zhou, Li
name: Zhou, X.
name: Zhou, X. K.
name: Zhou, X. R.
name: Zhou, X. Y.
name: Zhu, K.
name: Zhu, K. J.
name: Zhu, S.
name: Zhu, X. L.
name: Zhu, Y. C.
name: Zhu, Y. S.
name: Zhu, Z. A.
name: Zhuang, J.
name: Zotti, L.
name: Zou, B. S.
name: Zou, J. H.
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: We report the first observation of the Dalitz decay $η' \to γe^+e^-$, based on a data sample of 1.31 billion $J/ψ$ events collected with the BESIII detector. The $η'$ mesons are produced via the $J/ψ\to γη'$ decay process. The ratio $Γ(η' \to γe^+ e^-)/Γ(η'\toγγ)$ is measured to be $(2.13\pm0.09(\text{stat.})\pm0.07(\text{sys.}))\times10^{-2}$. This corresponds to a branching fraction ${\cal B}(η' \to γe^+e^-)= (4.69 \pm0.20(\text{stat.})\pm0.23(\text{sys.}))\times10^{-4}$. The transition form factor is extracted and different expressions are compared to the measured dependence on the $e^+e^-$ invariant mass. The results are consistent with the prediction of the Vector Meson Dominance model.
description: 11 pages,7 figures