Observation of Mixing-induced CP Violation in the Neutral B Meson System

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dc.creatorBelle Collaboration
dc.creatorAbe, K.
dc.date2002-02-13
dc.date2002-07-03
dc.date.accessioned2026-07-07T12:01:44Z
dc.date.available2026-07-07T12:01:44Z
dc.descriptionThis report describes an observation of mixing-induced CP violation and a measurement of the CP violation parameter, sin(2phi_1), with the Belle detector at the KEKB asymmetric e+e- collider. Using a data sample of 29.1 fb-1 recorded on the Upsilon(4S) resonance that contains 31.3 million BBbar pairs, we reconstruct decays of neutral B mesons to the following CP eigenstates: J/psi K_S^0, psi(2S) K_S^0, chi_c1 K_S^0, eta_c K_S^0, J/psi K_L^0 and J/psi K^*0. The flavor of the accompanying B meson is identified by combining information from primary and secondary leptons, K+/- mesons, lambda baryons, slow and fast pions. The proper-time interval between the two B meson decays is determined from the distance between the two decay vertices measured with a silicon vertex detector. The result sin(2phi_1) = 0.99 +/- 0.14(stat) +/- 0.06(syst) is obtained by applying a maximum likelihood fit to the 1137 candidate events. We conclude that there is large CP violation in the neutral B meson system. A zero value for sin(2phi_1) is ruled out by more than six standard deviations.
dc.description25 pages, 16 figures, accepted for publication in Physical Review D
dc.identifierhttps://arxiv.org/abs/hep-ex/0202027
dc.identifierhttp://arxiv.org/abs/hep-ex/0202027
dc.identifierPhys.Rev.D66:032007,2002
dc.identifierdoi:10.1103/PhysRevD.66.032007
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/207195
dc.subjectHigh Energy Physics - Experiment
dc.titleObservation of Mixing-induced CP Violation in the Neutral B Meson System
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