TY - JOUR

T1 - Measurement of Λ baryon polarization in e+e-→ΛΛ¯ at s=3.773 GeV

AU - BESIII Collaboration

AU - Ablikim, M.

AU - Achasov, M.  N

AU - Adlarson, P.

AU - Ahmed, S.

AU - Albrecht, M.

AU - Aliberti, R.

AU - Amoroso, A.

AU - An, M.  R

AU - An, Q.

AU - Bai, X.  H

AU - Bai, Y.

AU - Bakina, O.

AU - Baldini Ferroli, R.

AU - Balossino, I.

AU - Ban, Y.

AU - Begzsuren, K.

AU - Berger, N.

AU - Bertani, M.

AU - Bettoni, D.

AU - Bianchi, F.

AU - Bloms, J.

AU - Bortone, A.

AU - Boyko, I.

AU - Briere, R.  A

AU - Cai, H.

AU - Cai, X.

AU - Calcaterra, A.

AU - Cao, G.  F

AU - Cao, N.

AU - Cetin, S.  A

AU - Chang, J.  F

AU - Chang, W.  L

AU - Chelkov, G.

AU - Chen, D.  Y

AU - Chen, G.

AU - Chen, H.  S

AU - Chen, M.  L

AU - Chen, S.  J

AU - Chen, X.  R

AU - Chen, Y.  B

AU - Chen, Z.  J

AU - Cheng, W.  S

AU - Cibinetto, G.

AU - Cossio, F.

AU - Cui, X.  F

AU - Dai, H.  L

AU - Dai, J.  P

AU - Dai, X.  C

AU - Muchnoi, N.  Yu

AU - Nikolaev, I.  B

N1 - Funding Information: The BESIII collaboration thanks the staff of BEPCII and the IHEP computing center for their strong support. This work is supported in part by National Key R&D Program of China under Contracts No. 2020YFA0406400 and No. 2020YFA0406300; National Natural Science Foundation of China (NSFC) under Contracts No. 12075107, No. 11905236, No. 12047501, No. 11625523, No. 11635010, No. 11735014, No. 11822506, No. 11835012, No. 11935015, No. 11935016, No. 11935018, No. 11961141012, No. 12022510, No. 12025502, No. 12035009, No. 12035013, No. 12061131003; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contracts No. U1732263, No. U1832207; CAS Key Research Program of Frontier Sciences under Contract No. QYZDJ-SSW-SLH040; 100 Talents Program of CAS; Fundamental Research Funds for the Central Universities under Grants No. lzujbky-2021-sp24; Institute of Nuclear and Particle Physics, Astronomy and Cosmology and Shanghai Key Laboratory for Particle Physics and Cosmology; ERC under Contract No. 758462; European Union Horizon 2020 research and innovation programme under Contract No. Marie Sklodowska-Curie Grant Agreement No. 894790; German Research Foundation DFG under Contracts Nos. 443159800, Collaborative Research Center CRC 1044, GRK 214; Istituto Nazionale di Fisica Nucleare, Italy; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Science and Technology fund; Olle Engkvist Foundation under Contract No. 200-0605; STFC (United Kingdom); The Knut and Alice Wallenberg Foundation (Sweden) under Contract No. 2016.0157; The Royal Society, UK under Contracts No. DH140054 and No. DH160214; The Swedish Research Council; U.S. Department of Energy under Contracts No. DE-FG02-05ER41374, No. DE-SC-0012069. Publisher Copyright: Published by the American Physical Society

PY - 2022/1/1

Y1 - 2022/1/1

N2 - Using a data sample of ψ(3770) events collected with the BESIII detector at BEPCII corresponding to an integrated luminosity of 2.9 fb-1, we report a measurement of Λ spin polarization in e+e-→ΛΛ¯ at s=3.773 GeV. The significance of polarization is found to be 2σ including the systematic uncertainty, which implies a zero phase between the transition amplitudes of the ΛΛ¯ helicity states. This phase can be interpreted in terms of psionic form factors, and is determined to be ΔΦΨ=ΦEΨ-ΦMΨ=(71-46+66±5)°. Similarly, the ratio between the form factors is found to be Rψ=|GEΨ/GMΨ|=0.48-0.35+0.21±0.03. The first uncertainties are statistical and the second systematic.

AB - Using a data sample of ψ(3770) events collected with the BESIII detector at BEPCII corresponding to an integrated luminosity of 2.9 fb-1, we report a measurement of Λ spin polarization in e+e-→ΛΛ¯ at s=3.773 GeV. The significance of polarization is found to be 2σ including the systematic uncertainty, which implies a zero phase between the transition amplitudes of the ΛΛ¯ helicity states. This phase can be interpreted in terms of psionic form factors, and is determined to be ΔΦΨ=ΦEΨ-ΦMΨ=(71-46+66±5)°. Similarly, the ratio between the form factors is found to be Rψ=|GEΨ/GMΨ|=0.48-0.35+0.21±0.03. The first uncertainties are statistical and the second systematic.

UR - http://www.scopus.com/inward/record.url?scp=85122742261&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.105.L011101

DO - 10.1103/PhysRevD.105.L011101

M3 - Article

AN - SCOPUS:85122742261

VL - 105

JO - Physical Review D

JF - Physical Review D

SN - 2470-0010

IS - 1

M1 - L011101

ER -