A Search For The Rare Decays B To Pi L L And B0 To Eta L L

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ISBN 13 :
Total Pages : 190 pages
Book Rating : 4.:/5 (953 download)

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Download or read book Suppressed Charmed B Decay written by and published by . This book was released on 2009 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the measurement of the branching fractions of the suppressed charmed B0 → D*- a0+ decays and the non-resonant B0 → D*- [eta][pi]+ decays in approximately 230 million [Upsilon](4S) → B$\bar{B}$ events. The data have been collected with the BABAR detector at the PEP-II B factory at the Stanford Linear Accelerator Center in California. Theoretical predictions of the branching fraction of the B0 → D*- a0+ decays show large QCD model dependent uncertainties. Non-factorizing terms, in the naive factorization model, that can be calculated by QCD factorizing models have a large impact on the branching fraction of these decay modes. The predictions of the branching fractions are of the order of 10-6. The measurement of the branching fraction gives more insight into the theoretical models. In general a better understanding of QCD models will be necessary to conduct weak interaction physics at the next level. The presence of CP violation in electroweak interactions allows the differentiation between matter and antimatter in the laws of physics. In the Standard Model, CP violation is incorporated in the CKM matrix that describes the weak interaction between quarks. Relations amongst the CKM matrix elements are used to present the two relevant parameters as the apex of a triangle (Unitarity Triangle) in a complex plane. The over-constraining of the CKM triangle by experimental measurements is an important test of the Standard Model. At this moment no stringent direct measurements of the CKM angle [gamma], one of the interior angles of the Unitarity Triangle, are available. The measurement of the angle [gamma] can be performed using the decays of neutral B mesons. The B0 → D*- a0+ decay is sensitive to the angle [gamma] and, in comparison to the current decays that are being employed, could significantly enhance the measurement of this angle. However, the low expected branching fraction for the B0 → D*- a0+ decay channels could severely impact the measurement. A prerequisite of the measurement of the CKM angle is the observation of the B0 → D*- a0+ decay on which this thesis reports. The BABAR experiment consists of the BABAR detector and the PEP-II e+e- collider. The design of the experiment has been optimized for the study of CP violation in the decays of neutral B mesons but is also highly suitable for the search for rare B decays such as the B0 → D*- a0+ decay. The PEP-II collider operates at the [Upsilon](4S) resonance and is a clean source of B$\bar{B}$ meson pairs.