A study of the difference in the CP asymmetries between Lambdab0->J/Psi pi- and Lambdab0->J/PsipK- decays, DeltaACP, is performed using proton-proton collision data collected by the LHCb experiment in the years 2015-2018, corresponding to an integrated luminosity of 6fb-1. This quantity is measured to be Delta ACP=(4.03 \pm 1.18 \pm 0.23)%, where the first uncertainty is statistical and the second is systematic. When combined with the previous LHCb result, a value of Delta ACP=(4.31 \pm 1.06 \pm 0.28)% is obtained, corresponding to a significance of 3.9sigma against the CP symmetry hypothesis. Studies of triple-product asymmetries, which provide an additional probe of CP violation, show no significant deviation from CP symmetry.

First evidence of CP violation in beauty baryon to charmonium decays

Kleijne N.
Membro del Collaboration Group
;
Morello M. J.
Membro del Collaboration Group
;
Passaro D.
Membro del Collaboration Group
;
Pica L.
Membro del Collaboration Group
;
Riccardi D.
Membro del Collaboration Group
;
Xu A.
Membro del Collaboration Group
;
2026

Abstract

A study of the difference in the CP asymmetries between Lambdab0->J/Psi pi- and Lambdab0->J/PsipK- decays, DeltaACP, is performed using proton-proton collision data collected by the LHCb experiment in the years 2015-2018, corresponding to an integrated luminosity of 6fb-1. This quantity is measured to be Delta ACP=(4.03 \pm 1.18 \pm 0.23)%, where the first uncertainty is statistical and the second is systematic. When combined with the previous LHCb result, a value of Delta ACP=(4.31 \pm 1.06 \pm 0.28)% is obtained, corresponding to a significance of 3.9sigma against the CP symmetry hypothesis. Studies of triple-product asymmetries, which provide an additional probe of CP violation, show no significant deviation from CP symmetry.
2026
Settore FIS/01 - Fisica Sperimentale
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
B physics; CP violation; Flavour physics; LHCb experiment; Standard Model; Triple-product asymmetries
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/164864
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