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.| File | Dimensione | Formato | |
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