Observation of a Near-Threshold Structure in the K+ Recoil-Mass Spectra in e+e- →k+ (Ds- D∗0+ Ds∗- D0)

Date Issued
11-03-2021
Author(s)
Ablikim, M.
Achasov, M. N.
Adlarson, P.
Ahmed, S.
Albrecht, M.
Aliberti, R.
Amoroso, A.
An, Q.
Anita,
Bai, X. H.
Bai, Y.
Bakina, O.
Baldini Ferroli, R.
Balossino, I.
Ban, Y.
Begzsuren, K.
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, X. C.
Dbeyssi, A.
De Boer, R. B.
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.
Dong, X.
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, 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.
Guo, Y. P.
Guskov, A.
Han, T. T.
Hao, X. Q.
Harris, F. A.
DOI
Abstract
We report a study of the processes of e+e-→K+Ds-D∗0 and K+Ds∗-D0 based on e+e- annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb-1. An excess of events over the known contributions of the conventional charmed mesons is observed near the Ds-D∗0 and Ds∗-D0 mass thresholds in the K+ recoil-mass spectrum for events collected at s=4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5-2.6+1.8±2.1) MeV/c2 and (12.8-4.4+5.3±3.0) MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into Ds-D∗0 and Ds∗-D0. However, the properties of the excess need further exploration with more statistics.
Volume
126