Measurement of Λ transverse polarization in e+ e- collisions at √s=3.68-3.71 GeV

作者：Ablikim, M.; Achasov, M. N.; Adlarson, P.; Aliberti, R.; Amoroso, A.; An, M. R.; An, Q.; 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.; 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.; Chai, X. Y.; Chang, J. F.; Chang, T. T.; Chang, W. L.; Che, G. R.; Chelkov, G.; Chen, C.; Chen, Chao

来源：JOURNAL OF HIGH ENERGY PHYSICS, 2023, (10): 081.

DOI：10.1007/JHEP10(2023)081

• e(+)-e(-) Experiments
• Electroweak Interaction
• Polarization

With data samples collected with the BESIII detector at seven energy points at root s = 3.68 - 3.71 GeV, corresponding to an integrated luminosity of 333 pb(-1), we present a study of the Lambda transverse polarization in the e(+)e(-)->Lambda Lambda<overbar></mml:mover> reaction. The significance of polarization by combining the seven energy points is found to be 2.6 sigma including the systematic uncertainty, which implies a non-zero phase between the transition amplitudes of the Lambda(Lambda) over bar helicity states. The modulus ratio and the relative phase of EM-psionic form factors combined with all energy points are measured to be R-Psi = 0.71(-0.10)(+0.10) +/- 0.03 and Delta Phi(Psi) = 23(-8.0)(+8.8) +/- 1.6 degrees, where the first uncertainties are statistical and the second systematic.