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Title: A Study of Neutral B Meson Time Evolution Using Exclusively Reconstructed Semileptonic Decays

Abstract

The Standard Model of particle physics describes the fundamental building blocks of the Universe and their basic interactions. The model naturally describes the time evolution of the basic particles, of which lifetime and mixing are two examples. The neutral B meson, consisting of a bottom quark and an oppositely charged down quark, enjoys a lifetime of about 1.5 ps and the special property of mixing with its antiparticle partner, the {bar B}{sup 0}. That is, due to second order weak interactions, the B{sup 0} meson can change into a {bar B}{sup 0} meson and back again as it evolves through time. The details of this behavior offer an opportunity to closely examine the Standard Model. In this dissertation, I report on a measurement of the lifetime and mixing frequency of the neutral B meson. Using the semileptonic decay channel B{sup 0} {yields} D*{sup -}{ell}{sup +}{bar {nu}}{sub {ell}}, we select more than 68,000 signal and background candidates from about 23 million B{bar B} pairs collected in 1999-2000 with the BABAR detector located at the Stanford Linear Accelerator Center. The other B in the event is reconstructed inclusively. By constructing a master probability density function that describes the distribution of decay timemore » differences in the sample, we use a maximum likelihood technique to simultaneously extract the B{sup 0} lifetime and mixing parameters with precision comparable to the year 2000 world average. The results are {tau}{sub B{sup 0}} = (1.523{sub -0.023}{sup +0.024} {+-} 0.022) ps and {Delta}m{sub d} = (0.492 {+-} 0.018 {+-} 0.013) ps{sup -1}. The statistical correlation coefficient between {tau}{sub B{sup 0}} and {Delta}m{sub d} is -0.22. I describe in detail several cutting-edge strategies this analysis uses to study these phenomena, laying important groundwork for the future. I also discuss several extensions of this work to include possible measurements of higher order parameters such as {Delta}{Lambda}{sub d}.« less

Authors:
Publication Date:
Research Org.:
Stanford Linear Accelerator Center, Menlo Park, CA (US)
Sponsoring Org.:
USDOE Office of Science (US)
OSTI Identifier:
826559
Report Number(s):
SLAC-R-661
TRN: US0403419
DOE Contract Number:  
AC03-76SF00515
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 5 Nov 2003
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ACCURACY; ANTIPARTICLES; B MESONS; BASIC INTERACTIONS; DECAY; LIFETIME; MESONS; ORDER PARAMETERS; PHYSICS; PROBABILITY; QUARKS; SEMILEPTONIC DECAY; STANDARD MODEL; STANFORD LINEAR ACCELERATOR CENTER; WEAK INTERACTIONS

Citation Formats

Meyer, T. A Study of Neutral B Meson Time Evolution Using Exclusively Reconstructed Semileptonic Decays. United States: N. p., 2003. Web. doi:10.2172/826559.
Meyer, T. A Study of Neutral B Meson Time Evolution Using Exclusively Reconstructed Semileptonic Decays. United States. doi:10.2172/826559.
Meyer, T. Wed . "A Study of Neutral B Meson Time Evolution Using Exclusively Reconstructed Semileptonic Decays". United States. doi:10.2172/826559. https://www.osti.gov/servlets/purl/826559.
@article{osti_826559,
title = {A Study of Neutral B Meson Time Evolution Using Exclusively Reconstructed Semileptonic Decays},
author = {Meyer, T},
abstractNote = {The Standard Model of particle physics describes the fundamental building blocks of the Universe and their basic interactions. The model naturally describes the time evolution of the basic particles, of which lifetime and mixing are two examples. The neutral B meson, consisting of a bottom quark and an oppositely charged down quark, enjoys a lifetime of about 1.5 ps and the special property of mixing with its antiparticle partner, the {bar B}{sup 0}. That is, due to second order weak interactions, the B{sup 0} meson can change into a {bar B}{sup 0} meson and back again as it evolves through time. The details of this behavior offer an opportunity to closely examine the Standard Model. In this dissertation, I report on a measurement of the lifetime and mixing frequency of the neutral B meson. Using the semileptonic decay channel B{sup 0} {yields} D*{sup -}{ell}{sup +}{bar {nu}}{sub {ell}}, we select more than 68,000 signal and background candidates from about 23 million B{bar B} pairs collected in 1999-2000 with the BABAR detector located at the Stanford Linear Accelerator Center. The other B in the event is reconstructed inclusively. By constructing a master probability density function that describes the distribution of decay time differences in the sample, we use a maximum likelihood technique to simultaneously extract the B{sup 0} lifetime and mixing parameters with precision comparable to the year 2000 world average. The results are {tau}{sub B{sup 0}} = (1.523{sub -0.023}{sup +0.024} {+-} 0.022) ps and {Delta}m{sub d} = (0.492 {+-} 0.018 {+-} 0.013) ps{sup -1}. The statistical correlation coefficient between {tau}{sub B{sup 0}} and {Delta}m{sub d} is -0.22. I describe in detail several cutting-edge strategies this analysis uses to study these phenomena, laying important groundwork for the future. I also discuss several extensions of this work to include possible measurements of higher order parameters such as {Delta}{Lambda}{sub d}.},
doi = {10.2172/826559},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Nov 05 00:00:00 EST 2003},
month = {Wed Nov 05 00:00:00 EST 2003}
}

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