Novel aspects of baryon-antibaryon production in e+ e- annihilations
Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
* e-mail: Andrzej.Kupsc@physics.uu.se
Published online: 17 June 2019
Baryon-antibaryon decays of J/ψ and ψ‘ produced at an electron-positron collider are presented as a tool to study baryon properties and to test discrete symmetries. We focus on a novel aspect of this process: the transverse polarization of the produced baryons. The polarization was observed for first time by the BESIII Collaboration in e+e→ J/ψ → ΛΛ̅ . The observed spin polarization and correlations were used for a direct determination the Λ and Λ ̅ decay asymmetries. The result for Λ → pπ−, the well known Λ polarimeter process, diﬀers by 17(3)% from the established value of 0.642(13). Finally the prospects of the method for studies of weak decays of hyperons and for CP tests in baryon sector are discussed.
© The Authors, published by EDP Sciences, 2019
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