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arXiv · 1505.06283

Observation of the isospin-violating decay $J/\psi \to \phi\pi^{0}f_{0}(980)$

BESIII Collaboration·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. De dovich·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·X. Y. Gao·Y. Gao·Z. Gao·I. Garzia·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·Y. Guo·Y. P. Guo·Z. Haddadi·A. Haf ner·S. Han·Y. L. Han·X. Q. Hao·F. A. Harris·K. L. He·Z. Y. He·T. Held·Y. K. Heng·Z. L. Hou
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Abstract

Using a sample of 1.31 billion $J/\psi$ events collected with the BESIII detector at the BEPCII collider, the decays $J/\psi \to \phi \pi^{+}\pi^{-}\pi^{0}$ and $J/\psi \to \phi \pi^{0}\pi^{0}\pi^{0}$ are investigated. The isospin violating decay $J/\psi \to \phi \pi^{0} f_{0}(980)$ with $f_{0}(980) \to \pi\pi$, is observed for the first time. The width of the $f_{0}(980)$ obtained from the dipion mass spectrum is found to be much smaller than the world average value. In the $\pi^{0} f_{0}(980)$ mass spectrum, there is evidence of $f_1(1285)$ production. By studying the decay $J/\psi \to \phi\eta'$, the branching fractions of $\eta' \to \pi^{+}\pi^{-}\pi^{0}$ and $\eta' \to \pi^{0}\pi^{0}\pi^{0}$, as well as their ratio, are also measured.

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BESIII Collaboration, 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. De dovich, 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, X. Y. Gao, Y. Gao, Z. Gao, I. Garzia, 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, Y. Guo, Y. P. Guo, Z. Haddadi, A. Haf ner, S. Han, Y. L. Han, X. Q. Hao, F. A. Harris, K. L. He, Z. Y. He, T. Held, Y. K. Heng, Z. L. Hou. 2015-05-23. Observation of the isospin-violating decay $J/\psi \to \phi\pi^{0}f_{0}(980)$. https://doi.org/10.1103/physrevd.92.012007

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