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arXiv · 1303.7360

Measurement of $\eta^\prime\rightarrow \pi^+\pi^- e^+e^-$ and $\eta^\prime\rightarrow \pi^+\pi^-\mu^+\mu^-$

BESIII Collaboration·M. Ablikim·M. N. Achasov·O. Albayrak·D. J. Ambrose·F. F. An·Q. An·J. Z. Bai·R. Baldini Ferroli·Y. Ban·J. Becker·J. V. Bennett·M. Bertani·J. M. Bian·E. Boger·O. Bondarenko·I. Boyko·R. A. Briere·V. Bytev·H. Cai·X. Cai·O. akir·A. Calcaterra·G. F. Cao·S. A. Cetin·J. F. Chang·G. Chelkov·G. Chen·H. S. Chen·J. C. Chen·M. L. Chen·S. J. Chen·X. Chen·Y. B. Chen·H. P. Cheng·Y. P. Chu·D. Cronin-Hennessy·H. L. Dai·J. P. Dai·D. Dedovich·Z. Y. Deng·A. Denig·I. Denysenko·M. Destefanis·W. M. Ding·Y. Ding·L. Y. Dong·M. Y. Dong·S. X. Du·J. Fang·S. S. Fang·L. Fava·C. Q. Feng·P. Friedel·C. D. Fu·J. L. Fu·Y. Gao·C. Geng·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. P. Guo·Y. L. Han·F. A. Harris·K. L. He·M. He·Z. Y. He·T. Held·Y. K. Heng·Z. L. Hou·C. Hu·H. M. Hu·J. F. Hu·T. Hu·G. M. Huang·G. S. Huang·J. S. Huang·L. Huang·X. T. Huang·Y. Huang·Y. P. Huang·T. Hussain·C. S. Ji·Q. Ji·Q. P. Ji·X. B. Ji·X. L. Ji·L. L. Jiang·X. S. Jiang·J. B. Jiao·Z. Jiao·D. P. Jin·S. Jin
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Abstract

Based on a sample of 225.3 million J/\psi events accumulated with the BESIII detector at the BEPCII, the decays of \eta' to pi+pi-l+l- are studied via J/\psi to \gamma\eta'. A clear \eta' signal is observed in the pi+pi-e+e- mass spectrum, and the branching fraction is measured to be \BR(\eta' to pi+pi-e+e-) = (2.11\pm0.12 (stat.)\pm0.15 (syst.))\times10^{-3}, which is in good agreement with theoretical predictions and the previous measurement, but is determined with much higher precision. No \eta' signal is found in the pi+ pi- mu+ mu- mass spectrum, and the upper limit is determined to be \BR(\eta' to pi+ pi- mu+ mu-)<2.9\times10^{-5} at the 90% confidence level.

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BESIII Collaboration, M. Ablikim, M. N. Achasov, O. Albayrak, D. J. Ambrose, F. F. An, Q. An, J. Z. Bai, R. Baldini Ferroli, Y. Ban, J. Becker, J. V. Bennett, M. Bertani, J. M. Bian, E. Boger, O. Bondarenko, I. Boyko, R. A. Briere, V. Bytev, H. Cai, X. Cai, O. akir, A. Calcaterra, G. F. Cao, S. A. Cetin, J. F. Chang, G. Chelkov, G. Chen, H. S. Chen, J. C. Chen, M. L. Chen, S. J. Chen, X. Chen, Y. B. Chen, H. P. Cheng, Y. P. Chu, D. Cronin-Hennessy, H. L. Dai, J. P. Dai, D. Dedovich, Z. Y. Deng, A. Denig, I. Denysenko, M. Destefanis, W. M. Ding, Y. Ding, L. Y. Dong, M. Y. Dong, S. X. Du, J. Fang, S. S. Fang, L. Fava, C. Q. Feng, P. Friedel, C. D. Fu, J. L. Fu, Y. Gao, C. Geng, 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. P. Guo, Y. L. Han, F. A. Harris, K. L. He, M. He, Z. Y. He, T. Held, Y. K. Heng, Z. L. Hou, C. Hu, H. M. Hu, J. F. Hu, T. Hu, G. M. Huang, G. S. Huang, J. S. Huang, L. Huang, X. T. Huang, Y. Huang, Y. P. Huang, T. Hussain, C. S. Ji, Q. Ji, Q. P. Ji, X. B. Ji, X. L. Ji, L. L. Jiang, X. S. Jiang, J. B. Jiao, Z. Jiao, D. P. Jin, S. Jin. 2013-03-29. Measurement of $\eta^\prime\rightarrow \pi^+\pi^- e^+e^-$ and $\eta^\prime\rightarrow \pi^+\pi^-\mu^+\mu^-$. https://doi.org/10.1103/physrevd.87.092011

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