Measurement of the Absolute Branching Fraction and Decay Asymmetry of Λ →nγ

Date Issued
18-11-2022
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 radiative hyperon decay Λ→nγ is studied using (10087±44)×106 J/ψ events collected with the BESIII detector operating at BEPCII. The absolute branching fraction of the decay Λ→nγ is determined to be (0.832±0.038stat±0.054syst)×10-3, which is a factor of 2.1 lower and 5.6 standard deviations different than the previous measurement. By analyzing the joint angular distribution of the decay products, the first determination of the decay asymmetry αγ is reported with a value of -0.16±0.10stat±0.05syst.
Volume
129