Precision Measurement of the Decay ?+ →pγ in the Process J/ψ → ?+ ? ˉ -

作者：Ablikim, M.; Achasov, M.N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M.R.; An, Q.; Bai, Y.; Bakina, O.; Balossino, I.; Ban, Y.; Batozskaya, V.; Begzsuren, K.; Berger, N.; Bertani, M.; Bettoni, D.; Bianchi, F.; Bianco, E.; 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, T.T.; Chang, W.L.; Che, G.R.; Chelkov, G.; Chen, C.; Chen, Chao; Chen, G.; Chen, H.S.; Chen, M.L.; Chen, S.J.

来源：Physical Review Letters, 2023, 130(21): 211901.

DOI：10.1103/PhysRevLett.130.211901

• Absolute branching fractions
• Asymmetry parameter
• Average values
• Electron-positron colliders
• Hyperon decays
• Measurements of
• Precision measurement
• Standard deviation

Using (10 087±44)×106 J/ψ events collected with the BESIII detector, the radiative hyperon decay ?+→pγ is studied at an electron-positron collider experiment for the first time. The absolute branching fraction is measured to be (0.996±0.021stat±0.018syst)×10-3, which is lower than its world average value by 4.2 standard deviations. Its decay asymmetry parameter is determined to be -0.652±0.056stat±0.020syst. The branching fraction and decay asymmetry parameter are the most precise to date, and the accuracies are improved by 78% and 34%, respectively.
? 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.