@article{3b97936878b74387be0c5d1764ee77ea,
title = "ς+ and ς ¯-Polarization in the J/ψ and ψ (3686) Decays",
abstract = "From 1310.6×106 J/ψ and 448.1×106 ψ(3686) events collected with the BESIII experiment, we report the first observation of ς+ and ς¯-spin polarization in e+e-→J/ψ[ψ(3686)]→ς+ς¯-decays. The relative phases of the form factors Δφ have been measured to be (-15.5±0.7±0.5)° and (21.7±4.0±0.8)° with J/ψ and ψ(3686) data, respectively. The nonzero value of Δφ allows for a direct and simultaneous measurement of the decay asymmetry parameters of ς+→pπ0(α0=-0.998±0.037±0.009) and ς¯-→p¯π0(α¯0=0.990±0.037±0.011), the latter value being determined for the first time. The average decay asymmetry, (α0-α¯0)/2, is calculated to be-0.994±0.004±0.002. The CP asymmetry ACP,ς=(α0+α¯0)/(α0-α¯0)=-0.004±0.037±0.010 is extracted for the first time, and is found to be consistent with CP conservation.",
author = "{BESIII Collaboration} and M. Ablikim and Achasov, {M. N.} and P. Adlarson and S. Ahmed and M. Albrecht and A. Amoroso and Q. An and Anita and Y. Bai and O. Bakina and Ferroli, {R. Baldini} and I. Balossino and Y. Ban and K. Begzsuren and Bennett, {J. V.} and N. Berger and M. Bertani and D. Bettoni and F. Bianchi and J. Biernat and J. Bloms and A. Bortone and I. Boyko and Briere, {R. A.} and H. Cai and X. Cai and A. Calcaterra and Cao, {G. F.} and N. Cao and Cetin, {S. A.} and Chang, {J. F.} and Chang, {W. L.} and G. Chelkov and Chen, {D. Y.} and G. Chen and Chen, {H. S.} and Chen, {M. L.} and Chen, {S. J.} and Chen, {X. R.} and Chen, {Y. B.} and W. Cheng and G. Cibinetto and F. Cossio and Cui, {X. F.} and Dai, {H. L.} and Dai, {J. P.} and Dai, {X. C.} and A. Dbeyssi and Muchnoi, {N. Yu} and Nikolaev, {I. B.}",
note = "Publisher Copyright: {\textcopyright} 2020 authors. Published by the American Physical Society. Funded by SCOAP3. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.",
year = "2020",
month = jul,
day = "31",
doi = "10.1103/PhysRevLett.125.052004",
language = "English",
volume = "125",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "5",
}