First Evidence for Direct CP Violation in Beauty to Charmonium Decays

De Angelis, C.;Dettori, F.;Fabiano, F.;Manca, G.;Oldeman, R.;Provenzano, D.;Saitta, B.;
2025-01-01

Abstract

The CP asymmetry and branching fraction of the Cabibbo-Kobayashi-Maskawa-suppressed decay B+→J/ψπ+ are precisely measured relative to the favored decay B+→J/ψK+ using a sample of proton-proton collision data corresponding to an integrated luminosity of 5.4 fb-1 recorded at a center-of-mass energy of 13 TeV during 2016-2018. The results of the CP asymmetry difference and branching fraction ratio are ΔACPACP(B+→J/ψπ+)-ACP(B+→J/ψK+)=(1.29±0.49±0.08)×10-2, Rπ/K[B(B+→J/ψπ+)/B(B+→J/ψK+)]=(3.852±0.022±0.018)×10-2, where the first uncertainties are statistical and the second are systematic. A combination with previous LHCb results based on data collected at 7 and 8 TeV in 2011 and 2012 yields ΔACP=(1.42±0.43±0.08)×10-2 and Rπ/K=(3.846±0.018±0.018)×10-2. The combined ΔACP value deviates from zero by 3.2 standard deviations, providing the first evidence for direct CP violation in the amplitudes of beauty decays to charmonium final states.
2025
Inglese
134
10
101801
13
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.134.101801
Esperti anonimi
scientifica
Aaij, R.; Abdelmotteleb, A.  S.  W.; Abellan Beteta, C.; Abudinén, F.; Ackernley, T.; Adefisoye, A.  A.; Adeva, B.; Adinolfi, M.; Adlarson, P.; Agapop ...espandi
1.1 Articolo in rivista
info:eu-repo/semantics/article
1 Contributo su Rivista::1.1 Articolo in rivista
262
1152
open
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