Вы находитесь на старом сайте НГУ. Перейти на новый сайт

Measurement of the matrix elements for the decays η′ →ηπ+π- and η′ →ηπ0π0

Ablikim M., Achasov M. N., Ahmed S., Albrecht M., Amoroso A., An F. F., An Q., Bai J. Z., Bai Y., Bakina O., Baldini Ferroli R., Ban Y., Bennett D. W., Bennett J. V., Berger N., Bertani M., Bettoni D., Bian J. M., Bianchi F., Boger E., Boyko I., Briere R. A., Cai H., Cai X., Cakir O., Calcaterra A., Cao G. F., Cetin S. A., Chai J., Chang J. F., Chelkov G., Chen G., Chen H. S., Chen J. C., Chen M. L., Chen S. J., Chen X. R., Chen Y. B., Chu X. K., Cibinetto G., 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., Dorjkhaidav O., Dou Z. L., Du S. X., Duan P. F., Fang J., Fang S. S., Fang X., Fang Y., Farinelli R., Fava L., Fegan S., Feldbauer F., Felici G., Feng C. Q., Fioravanti E., Fritsch M., Fu C. D., Gao Q.

© 2018 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP 3 . Based on a sample of 1.31×109 J/ψ events collected with the BESIII detector, the matrix elements for the decays η′→ηπ+π- and η′→ηπ0π0 are determined using 351,016 η′→(η→γγ)π+π- and 56,249 η′→(η→γγ)π0π0 events with background levels less than 1%. Two commonly used representations are used to describe the Dalitz plot density. We find that an assumption of a linear amplitude does not describe the data well. A small deviation of the obtained matrix elements between η′→ηπ+π- and η′→ηπ0π0 is probably caused by the mass difference between charged and neutral pions or radiative corrections. No cusp structure in η′→ηπ0π0 is observed.