Observation of ηc (2S) →3 (π+π-) and measurements of χcJ →3 (π+π-) in ψ (3686) radiative transitions

Date Issued
01-08-2022
Author(s)
Ablikim, M.
Achasov, M. N.
Adlarson, P.
Albrecht, M.
Aliberti, R.
Amoroso, A.
An, M. R.
An, Q.
Bai, X. H.
Bai, Y.
Bakina, O.
Baldini Ferroli, R.
Balossino, I.
Ban, Y.
Batozskaya, V.
Becker, D.
Begzsuren, K.
Berger, N.
Bertani, M.
Bettoni, D.
Bianchi, F.
Bloms, J.
Bortone, A.
Boyko, I.
Briere, R. A.
Brueggemann, A.
Cai, H.
Cai, X.
Calcaterra, A.
Cao, G. F.
Cao, N.
Cetin, S. A.
Chang, J. F.
Chang, W. L.
Chelkov, G.
Chen, C.
Chen, Chao
Chen, G.
Chen, H. S.
Chen, M. L.
Chen, S. J.
Chen, S. M.
Chen, T.
Chen, X. R.
Chen, X. T.
Chen, Y. B.
Chen, Z. J.
Cheng, W. S.
Choi, S. K.
Chu, X.
Cibinetto, G.
Cossio, F.
Cui, J. J.
Dai, H. L.
Dai, J. P.
Dbeyssi, A.
De Boer, R. E.
Dedovich, D.
Deng, Z. Y.
Denig, A.
Denysenko, I.
Destefanis, M.
De Mori, F.
Ding, Y.
Dong, J.
Dong, L. Y.
Dong, M. Y.
Dong, X.
Du, S. X.
Egorov, P.
Fan, Y. L.
Fang, J.
Fang, S. S.
Fang, W. X.
Fang, Y.
Farinelli, R.
Fava, L.
Feldbauer, F.
Felici, G.
Feng, C. Q.
Feng, J. H.
Fischer, K.
Fritsch, M.
Fritzsch, C.
Fu, C. D.
Gao, H.
Gao, Y. N.
Gao, Yang
Garbolino, S.
Garzia, I.
Ge, P. T.
Ge, Z. W.
Geng, C.
Gersabeck, E. M.
Gilman, A.
Goetzen, K.
Gong, L.
Gong, W. X.
Gradl, W.
Greco, M.
DOI
Abstract
The hadronic decay ηc(2S)→3(π+π-) is observed with a statistical significance of 9.3 standard deviations using (448.1±2.9)×106 ψ(3686) events collected by the BESIII detector at the BEPCII collider. The measured mass and width of ηc(2S) are (3643.4±2.3 (stat)±4.4 (syst)) MeV/c2 and (19.8±3.9 (stat)±3.1 (syst)) MeV, respectively, which are consistent with the world average values within two standard deviations. The product branching fraction B[ψ(3686)→γηc(2S)]×B[ηc(2S)→3(π+π-)] is measured to be (9.2±1.0 (stat)±1.2 (syst))×10-6. Using B[ψ(3686)→γηc(2S)]=(7.0-2.5+3.4)×10-4, we obtain B[ηc(2S)→3(π+π-)]=(1.31±0.15 (stat)±0.17 (syst) (+0.64-0.47) (extr))×10-2, where the third uncertainty is from B[ψ(3686)→γηc(2S)]. We also measure the χcJ→3(π+π-) (J=0, 1, 2) decays via ψ′→γχcJ transitions. The branching fractions are B[χc0→3(π+π-)]=(2.080±0.006 (stat)±0.068 (syst))×10-2, B[χc1→3(π+π-)]=(1.092±0.004 (stat)±0.035 (syst))×10-2, and B[χc2→3(π+π-)]=(1.565±0.005 (stat)±0.048 (syst))×10-2.
Volume
106