Measurements of Born cross sections for e+e- → Λc+ Λ ¯ c (2595)-+ c. c. and e+e- → Λc+ Λ ¯ c (2625)-+ c. c. at s =4918.0 and 4950.9 MeV

Journal
Physical Review D
ISSN
24700010
Date Issued
2024-04-01
Author(s)
Ablikim, M.
Achasov, M. N.
Adlarson, P.
Afedulidis, O.
Ai, X. C.
Aliberti, R.
Amoroso, A.
An, Q.
Bai, Y.
Bakina, O.
Balossino, I.
Ban, Y.
Bao, H. R.
Batozskaya, V.
Begzsuren, K.
Berger, N.
Berlowski, M.
Bertani, M.
Bettoni, D.
Bianchi, F.
Bianco, E.
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.
Che, G. R.
Chelkov, G.
Chen, C.
Chen, C. H.
Chen, Chao
Chen, G.
Chen, H. S.
Chen, M. L.
Chen, S. J.
Chen, S. L.
Chen, S. M.
Chen, T.
Chen, X. R.
Chen, X. T.
Chen, Y. B.
Chen, Y. Q.
Chen, Z. J.
Chen, Z. Y.
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, C. Q.
Deng, Z. Y.
Denig, A.
Denysenko, I.
Destefanis, M.
De Mori, F.
Ding, B.
Ding, X. X.
Ding, Y.
Ding, Y.
Dong, J.
Dong, L. Y.
Dong, M. Y.
Dong, X.
Du, M. C.
Du, S. X.
Duan, Z. H.
Egorov, P.
Fan, Y. H.
Fang, J.
Fang, J.
Fang, S. S.
Fang, W. X.
Fang, Y.
Fang, Y. Q.
Farinelli, R.
Fava, L.
Feldbauer, F.
Felici, G.
Feng, C. Q.
Feng, J. H.
Feng, Y. T.
Fischer, K.
Fritsch, M.
Fu, C. D.
Fu, J. L.
Fu, Y. W.
Gao, H.
Gao, Y. N.
DOI
Abstract
Using e+e- collision data collected with the BESIII detector operating at the BEPCII collider, the Born cross sections of e+e-→Λc+Λ¯c(2595)-+c.c. and e+e-→Λc+Λ¯c(2625)-+c.c. are measured for the first time at center-of-mass energies of s=4918.0 and 4950.9 MeV. Nonzero cross sections are observed very close to the production threshold. The measured Born cross sections of e+e-→Λc+Λ¯c(2625)-+c.c. are about 2-3 times greater than those of e+e-→Λc+Λ¯c(2595)-+c.c., providing the similar behavior as semileptonic decays of Λb0, but different behavior from that in the hadronic decays of Λb0. The Born cross sections are 15.6±3.1±0.9 pb and 29.4±3.7±2.7 pb for e+e-→Λc+Λ¯c(2595)-+c.c., and are 43.4±4.0±4.1 pb and 76.8±6.5±4.2 pb for e+e-→Λc+Λ¯c(2625)-+c.c. at s=4918.0 and 4950.9 MeV, respectively. Based on the polar angle distributions of the Λ¯c(2625)- and Λc(2625)+, the form-factor ratios |GE|2+3|GM|2/|GC| are determined for e+e-→Λc+Λ¯c(2625)-+c.c. for the first time, which are 5.95±4.07±0.15 and 0.94±0.32±0.02 at s=4918.0 and 4950.9 MeV, respectively. All of these first uncertainties are statistical and second systematic.
Volume
109