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Title: CP Violation in B Mesons

Abstract

Symmetries and their conservation laws play a fundamental role in Physics. Among them, the discrete symmetries corresponding to charge (C), parity (P), and time (T) transformations are extensively used in the theory of the elementary particles and their interactions (so called Standard Model (SM)) to give the basis of the fundamental physical description of nature. Eventual discoveries of violations of these symmetries become a crucial test for our understanding of the nature. It was assumed that the three discrete symmetries were not violated until 1956 when it was found that P is violated in the weak interaction. Soon it was understood that also the C is violated in the weak interaction. At that time these two violated symmetries were replaced by their combination, CP, which was considered a new fundamental symmetry. In 1964 also the CP was found violated in the case of the neutral K meson system. Since that year there were many achievements in theories and experiments in order to explain this symmetry violation. In the last five years the main contribution comes from the discovery of the CP violation in B meson system. In this note we will describe briefly how the CP violation is described inmore » the SM and the main experimental results obtained in the B mesons system.« less

Authors:
;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
903304
Report Number(s):
SLAC-PUB-12440
TRN: US0703358
DOE Contract Number:
AC02-76SF00515
Resource Type:
Conference
Resource Relation:
Conference: Presented at 45th International Meeting on Nuclear Physics, Bormio, Italy, 14-21 Jan 2007
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; B MESONS; CONSERVATION LAWS; ELEMENTARY PARTICLES; MESONS; NUCLEAR PHYSICS; PARITY; PHYSICS; STANDARD MODEL; SYMMETRY; TRANSFORMATIONS; WEAK INTERACTIONS; Experiment-HEP,HEPEX

Citation Formats

Lazzaro, Alfio, and /Milan U. /INFN, Milan. CP Violation in B Mesons. United States: N. p., 2007. Web.
Lazzaro, Alfio, & /Milan U. /INFN, Milan. CP Violation in B Mesons. United States.
Lazzaro, Alfio, and /Milan U. /INFN, Milan. Fri . "CP Violation in B Mesons". United States. doi:. https://www.osti.gov/servlets/purl/903304.
@article{osti_903304,
title = {CP Violation in B Mesons},
author = {Lazzaro, Alfio and /Milan U. /INFN, Milan},
abstractNote = {Symmetries and their conservation laws play a fundamental role in Physics. Among them, the discrete symmetries corresponding to charge (C), parity (P), and time (T) transformations are extensively used in the theory of the elementary particles and their interactions (so called Standard Model (SM)) to give the basis of the fundamental physical description of nature. Eventual discoveries of violations of these symmetries become a crucial test for our understanding of the nature. It was assumed that the three discrete symmetries were not violated until 1956 when it was found that P is violated in the weak interaction. Soon it was understood that also the C is violated in the weak interaction. At that time these two violated symmetries were replaced by their combination, CP, which was considered a new fundamental symmetry. In 1964 also the CP was found violated in the case of the neutral K meson system. Since that year there were many achievements in theories and experiments in order to explain this symmetry violation. In the last five years the main contribution comes from the discovery of the CP violation in B meson system. In this note we will describe briefly how the CP violation is described in the SM and the main experimental results obtained in the B mesons system.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri May 11 00:00:00 EDT 2007},
month = {Fri May 11 00:00:00 EDT 2007}
}

Conference:
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  • We report recent studies of CP-violation and mixing in neutral B mesons from the CDF experiment at the Fermilab Tevatron Collider. Results of a direct measurement of the CP-violation parameter sin 2{beta} using B{sup 0} {yields} J/{psi}K{sub S}{sup 0} with multi flavor tagging algorithms, a search for B{sub s}{sup 0} - {bar B}{sub s}{sup 0} mixing using semileptonic decays, and the updated precision measurements of the B{sup 0} - {bar B}{sup 0} mixing parameter will be presented. The prospects for B physics with the upgraded CDF detector in the next Tevatron Collider run will also be discussed.
  • We consider the contribution of e/sup /plus//e/sup /minus// machines to the measurement of CP violation in the B systems. Energy regions from the GAMMA(4S) to the Z/degree/ are considered, problems and prospects at each energy are reviewed.
  • A D0 analysis measuring the charge asymmetry A{sub sl}{sup b} of like-sign dimuon events due to semileptonic b-hadron decays at the Fermilab Tevatron Collider is described. It differs by 3.2 standard deviations from the Standard Model prediction to provide first evidence of CPT-invariant anomalous CP violation in the mixing of neutral B mesons, and is compared to the CP-violating phase obtained from a D0 analysis of the time-dependent decay angles in B{sub s}{sup 0} {yields} J/{psi}{phi}. If CPT violation is allowed, the dimuon asymmetry also yields the first sensitivity to CPT violation in the B{sub s}{sup 0} system.
  • If CP violation comes from complex phases in the quark mixing matrix, then neutral B decays to CP eigenstates will exhibit large, cleanly-predicted CP-violating effects. The authors show that the same is true of neutral B decays to several types of ``near-CP-eigenstates.`` By experimentally studying the latter decays as well as those to the CP eigenstates, one will be able to obtain more definitive information on CP violation from a given number of B mesons.
  • B{sup 0} mixing measurements from the Tevatron Run I data are reported. These include time-integrated measurements of the average mixing pa- rameter {bar {chi}}, six time-dependent oscillation measurements of {Delta}m{sub d}, and a time-dependent limit on {Delta}m{sub s}. Such measurements provide constraints on CKM matrix elements. A sample of B{sup 0}/{anti B}{sup 0} {yields} J/{psi}K{sup 0}{sub S} decays is used to directly measure the CP -violation parameter sin(2{beta}). This value agrees well with indirect constraints on the CKM matrix.