A stringent test of CP symmetry in hyperon decays is performed using 1.0×1010J/ψ events and 2.7×109ψ(3686) events collected by the BESIII experiment. The CP asymmetry in the two-body nonleptonic weak decays Σ+→pπ0 and Σ¯-→p¯π0 is determined to be ACP=-0.0118±0.0083(stat)±0.0028(syst), consistent with CP conservation. The average decay parameter ⟨α0⟩=-0.9869±0.0011(stat)±0.0016(syst) represents the most precise measurement in the baryon sector to date. A model-independent analysis of the hyperon polarization is performed for the first time at J/ψ and ψ(3686) resonances, revealing a clear sign reversal and offering new insight into SU(3) symmetry breaking and baryon internal structure. These results provide the most stringent constraints on CP violation in Σ decays and establish a benchmark for future precision studies.

Precision CP Symmetry Test and Polarization Analysis in Σ+ Decays

Amoroso, A.;Bianchi, F.;Destefanis, M.;De Mori, F.;Greco, M.;Maggiora, M.;Marcello, S.;Sosio, S.;Spataro, S.;
2025-01-01

Abstract

A stringent test of CP symmetry in hyperon decays is performed using 1.0×1010J/ψ events and 2.7×109ψ(3686) events collected by the BESIII experiment. The CP asymmetry in the two-body nonleptonic weak decays Σ+→pπ0 and Σ¯-→p¯π0 is determined to be ACP=-0.0118±0.0083(stat)±0.0028(syst), consistent with CP conservation. The average decay parameter ⟨α0⟩=-0.9869±0.0011(stat)±0.0016(syst) represents the most precise measurement in the baryon sector to date. A model-independent analysis of the hyperon polarization is performed for the first time at J/ψ and ψ(3686) resonances, revealing a clear sign reversal and offering new insight into SU(3) symmetry breaking and baryon internal structure. These results provide the most stringent constraints on CP violation in Σ decays and establish a benchmark for future precision studies.
2025
135
14
141804-1
141804-10
Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ai, X. C.; Aliberti, R.; Amoroso, A.; An, Q.; Bai, Y.; Bakina, O.; Ban, Y.; Bao, H.-R.; Batozskaya, V.; Beg...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/2118036
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