Observation of CP violation in the B° meson system

B Aubert; Paul Bright-Thomas; Theresa Harrison; Christopher Hawkes; David Knowles; Stephen O'Neale; Richard Penny; Alan Watson; Nigel Watson

doi:10.1103/PhysRevLett.87.091801

Observation of CP violation in the B° meson system

B Aubert, Paul Bright-Thomas, Theresa Harrison, Christopher Hawkes, David Knowles, Stephen O'Neale, Richard Penny, Alan Watson, Nigel Watson

Physics and Astronomy

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Abstract

We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully reconstructed in a final state containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2 beta, is derived from the decay time distributions in such events. The result sin2 beta = 0.59+/-0.14(stat)+/-0.05(syst) establishes CP violation in the B(0) meson system. We also determine absolute value of lambda = 0.93+/-0.09(stat)+/-0.03(syst), consistent with no direct CP violation.

Original language	English
Pages (from-to)	091801
Number of pages	1
Journal	Physical Review Letters
Volume	87
Issue number	9
Early online date	1 Aug 2001
DOIs	https://doi.org/10.1103/PhysRevLett.87.091801
Publication status	Published - 1 Aug 2001

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title = "Observation of CP violation in the B° meson system",

abstract = "We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully reconstructed in a final state containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2 beta, is derived from the decay time distributions in such events. The result sin2 beta = 0.59+/-0.14(stat)+/-0.05(syst) establishes CP violation in the B(0) meson system. We also determine absolute value of lambda = 0.93+/-0.09(stat)+/-0.03(syst), consistent with no direct CP violation.",

author = "B Aubert and Paul Bright-Thomas and Theresa Harrison and Christopher Hawkes and David Knowles and Stephen O'Neale and Richard Penny and Alan Watson and Nigel Watson",

year = "2001",

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doi = "10.1103/PhysRevLett.87.091801",

language = "English",

volume = "87",

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TY - JOUR

T1 - Observation of CP violation in the B° meson system

AU - Aubert, B

AU - Bright-Thomas, Paul

AU - Harrison, Theresa

AU - Hawkes, Christopher

AU - Knowles, David

AU - O'Neale, Stephen

AU - Penny, Richard

AU - Watson, Alan

AU - Watson, Nigel

PY - 2001/8/1

Y1 - 2001/8/1

N2 - We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully reconstructed in a final state containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2 beta, is derived from the decay time distributions in such events. The result sin2 beta = 0.59+/-0.14(stat)+/-0.05(syst) establishes CP violation in the B(0) meson system. We also determine absolute value of lambda = 0.93+/-0.09(stat)+/-0.03(syst), consistent with no direct CP violation.

AB - We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully reconstructed in a final state containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the standard model is proportional to sin2 beta, is derived from the decay time distributions in such events. The result sin2 beta = 0.59+/-0.14(stat)+/-0.05(syst) establishes CP violation in the B(0) meson system. We also determine absolute value of lambda = 0.93+/-0.09(stat)+/-0.03(syst), consistent with no direct CP violation.

U2 - 10.1103/PhysRevLett.87.091801

DO - 10.1103/PhysRevLett.87.091801

M3 - Article

C2 - 11531560

SN - 1079-7114

VL - 87

SP - 091801

JO - Physical Review Letters

JF - Physical Review Letters

IS - 9

ER -

Observation of CP violation in the B° meson system

Abstract

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