Observation of Resonance Structures in e+e- →π+π-ψ2 (3823) and Mass Measurement of ψ2 (3823)

Date Issued
02-09-2022
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, G.
Chen, H. S.
Chen, M. L.
Chen, S. J.
Chen, T.
Chen, X. R.
Chen, X. T.
Chen, Y. B.
Chen, Z. J.
Cheng, W. S.
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, Y.
Farinelli, R.
Fava, L.
Feldbauer, F.
Felici, G.
Feng, C. Q.
Feng, J. H.
Fischer, K.
Fritsch, M.
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.
Gu, L. M.
Gu, M. H.
Gu, Y. T.
Guan, C. Y.
Guo, A. Q.
Guo, L. B.
DOI
Abstract
Using a data sample corresponding to an integrated luminosity of 11.3 fb-1 collected at center-of-mass energies from 4.23 to 4.70 GeV with the BESIII detector, we measure the product of the e+e-→π+π-ψ2(3823) cross section and the branching fraction B[ψ2(3823)→γχc1]. For the first time, resonance structure is observed in the cross section line shape of e+e-→π+π-ψ2(3823) with significances exceeding 5σ. A fit to data with two coherent Breit-Wigner resonances modeling the s-dependent cross section yields M(R1)=4406.9±17.2±4.5 MeV/c2, Γ(R1)=128.1±37.2±2.3 MeV, and M(R2)=4647.9±8.6±0.8 MeV/c2, Γ(R2)=33.1±18.6±4.1 MeV. Though weakly disfavored by the data, a single resonance with M(R)=4417.5±26.2±3.5 MeV/c2, Γ(R)=245±48±13 MeV is also possible to interpret data. This observation deepens our understanding of the nature of the vector charmoniumlike states. The mass of the ψ2(3823) state is measured as (3823.12±0.43±0.13) MeV/c2, which is the most precise measurement to date.
Volume
129