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arXiv · 1507.06734

Observation of $\eta^{\prime}\to\omega e^{+} e^{-}$

M. Ablikim·M. N. Achasov·X. C. Ai·O. Albayrak·M. Albrecht·D. J. Ambrose·A. Amoroso·F. F. An·Q. An·J. Z. Bai·R. Baldini Ferroli·Y. Ban·D. W. Bennett·J. V. Bennett·M. Bertani·D. Bettoni·J. M. Bian·F. Bianchi·E. Boger·O. Bondarenko·I. Boyko·R. A. Briere·H. Cai·X. Cai·O. Cakir·A. Calcaterra·G. F. Cao·S. A. Cetin·J. F. Chang·G. Chelkov·G. Chen·H. S. Chen·H. Y. Chen·J. C. Chen·M. L. Chen·S. J. Chen·X. Chen·X. R. Chen·Y. B. Chen·H. P. Cheng·X. K. Chu·G. Cibinetto·D. Cronin-Hennessy·H. L. Dai·J. P. Dai·A. Dbeyssi·D. Dedovich·Z. Y. Deng·A. Denig·I. Denysenko·M. Destefanis·F. De Mori·Y. Ding·C. Dong·J. Dong·L. Y. Dong·M. Y. Dong·S. X. Du·P. F. Duan·J. Z. Fan·J. Fang·S. S. Fang·X. Fang·Y. Fang·L. Fava·F. Feldbauer·G. Felici·C. Q. Feng·E. Fioravanti·M. Fritsch·C. D. Fu·Q. Gao·Y. Gao·I. Garzia·K. Goetzen·W. X. Gong·W. Gradl·M. Greco·M. H. Gu·Y. T. Gu·Y. H. Guan·A. Q. Guo·L. B. Guo·T. Guo·Y. Guo·Y. P. Guo·Z. Haddadi·A. Hafner·S. Han·Y. L. Han·F. A. Harris·K. L. He·Z. Y. He·T. Held·Y. K. Heng·Z. L. Hou·C. Hu·H. M. Hu·J. F. Hu·T. Hu
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Abstract

Based on a sample of \etapr mesons produced in the radiative decay $J/\psi\to\gamma\eta^{\prime}$ in $1.31\times 10^9$ $J/\psi$ events collected with the BESIII detector, the decay $\eta^{\prime}\to\omega e^{+} e^{-}$ is observed for the first time, with a statistical significance of $8\sigma$. The branching fraction is measured to be $\mathcal{B}(\eta^{\prime}\to\omega e^{+} e^{-})=(1.97\pm0.34(\text{stat})\pm0.17(\text{syst}))\times10^{-4}$, which is in agreement with theoretical predictions. The branching fraction of $\eta^{\prime}\to\omega\gamma$ is also measured to be $(2.55\pm0.03(\text{stat})\pm0.16(\text{syst}))\times10^{-2}$, which is the most precise measurement to date, and the relative branching fraction $\frac{\mathcal{B}(\eta^{\prime}\to \omega e^{+}e^{-})}{\mathcal{B}(\eta^{\prime}\to \omega \gamma)}$ is determined to be $(7.71\pm1.34(\text{stat})\pm0.54(\text{syst}))\times10^{-3}$.

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M. Ablikim, M. N. Achasov, X. C. Ai, O. Albayrak, M. Albrecht, D. J. Ambrose, A. Amoroso, F. F. An, Q. An, J. Z. Bai, R. Baldini Ferroli, Y. Ban, D. W. Bennett, J. V. Bennett, M. Bertani, D. Bettoni, J. M. Bian, F. Bianchi, E. Boger, O. Bondarenko, I. Boyko, R. A. Briere, H. Cai, X. Cai, O. Cakir, A. Calcaterra, G. F. Cao, S. A. Cetin, J. F. Chang, G. Chelkov, G. Chen, H. S. Chen, H. Y. Chen, J. C. Chen, M. L. Chen, S. J. Chen, X. Chen, X. R. Chen, Y. B. Chen, H. P. Cheng, X. K. Chu, G. Cibinetto, D. Cronin-Hennessy, H. L. Dai, J. P. Dai, A. Dbeyssi, D. Dedovich, Z. Y. Deng, A. Denig, I. Denysenko, M. Destefanis, F. De Mori, Y. Ding, C. Dong, J. Dong, L. Y. Dong, M. Y. Dong, S. X. Du, P. F. Duan, J. Z. Fan, J. Fang, S. S. Fang, X. Fang, Y. Fang, L. Fava, F. Feldbauer, G. Felici, C. Q. Feng, E. Fioravanti, M. Fritsch, C. D. Fu, Q. Gao, Y. Gao, I. Garzia, K. Goetzen, W. X. Gong, W. Gradl, M. Greco, M. H. Gu, Y. T. Gu, Y. H. Guan, A. Q. Guo, L. B. Guo, T. Guo, Y. Guo, Y. P. Guo, Z. Haddadi, A. Hafner, S. Han, Y. L. Han, F. A. Harris, K. L. He, Z. Y. He, T. Held, Y. K. Heng, Z. L. Hou, C. Hu, H. M. Hu, J. F. Hu, T. Hu. 2015-07-24. Observation of $\eta^{\prime}\to\omega e^{+} e^{-}$. https://doi.org/10.1103/physrevd.92.051101

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