Options
Measurement of the branching fraction of and search for a CP -violating asymmetry in η′ →π+π-e+e- At BESIII
Date Issued
19-05-2021
Author(s)
Ablikim, M.
Achasov, M. N.
Adlarson, P.
Ahmed, S.
Albrecht, M.
Amoroso, A.
An, Q.
Bai, X. H.
Bai, Y.
Bakina, O.
Ferroli, R. Baldini
Balossino, I.
Ban, Y.
Begzsuren, K.
Bennett, J. V.
Berger, N.
Bertani, M.
Bettoni, D.
Bianchi, F.
Biernat, J.
Bloms, J.
Bortone, A.
Boyko, I.
Briere, R. A.
Cai, H.
Cai, X.
Calcaterra, A.
Cao, G. F.
Cao, N.
Cetin, S. A.
Chang, J. F.
Chang, W. L.
Chelkov, G.
Chen, D. Y.
Chen, G.
Chen, H. S.
Chen, M. L.
Chen, S. J.
Chen, X. R.
Chen, Y. B.
Chen, Z. J.
Cheng, W. S.
Cibinetto, G.
Cossio, F.
Cui, X. F.
Dai, H. L.
Dai, J. P.
Dai, X. C.
Dbeyssi, A.
De Boer, R. E.
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.
Du, S. X.
Fang, J.
Fang, S. S.
Fang, Y.
Farinelli, R.
Fava, L.
Feldbauer, F.
Felici, G.
Feng, C. Q.
Fritsch, M.
Fu, C. D.
Fu, Y.
Gao, X. L.
Gao, Y.
Gao, Y.
Gao, Y.
Gao, Y. G.
Garzia, I.
Gersabeck, E. M.
Gilman, A.
Goetzen, K.
Gong, L.
Gong, W. X.
Gradl, W.
Greco, M.
Gu, L. M.
Gu, M. H.
Gu, S.
Gu, Y. T.
Guan, C. Y.
Guo, A. Q.
Guo, L. B.
Guo, R. P.
Guo, Y. P.
Guskov, A.
Han, S.
Han, T. T.
Han, T. Z.
Hao, X. Q.
Abstract
The rare decay η′→π+π-e+e- is studied using a sample of 1.3×109 J/ψ events collected with the BESIII detector at BEPCII in 2009 and 2012. The branching fraction is measured with improved precision to be (2.42±0.05stat±0.08syst)×10-3. Due to the inclusion of new data, this result supersedes the last BESIII result on this branching fraction. In addition, the CP-violating asymmetry in the angle between the decay planes of the π+π - pair and the e+e - pair is investigated. A measurable value would indicate physics beyond the standard model; the result is ACP=(2.9±3.7stat±1.1syst)%, which is consistent with the standard model expectation of no CP-violation. The precision is comparable to the asymmetry measurement in the KL0→π+π-e+e- decay where the observed (14±2)% effect is driven by a standard model mechanism.
Volume
103