Time Dependent Analysis of B to rho0rho0 Decays

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The BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider is located at the Stanford Linear Accelerator Center. It has been gathering data on the {Upsilon}(4S) resonance from 2000 until 2007 with the primary objective of studying CP violation in B-meson decays. In this thesis they provide a theoretical overview of how CP violation arises in the context of the Standard Model, why B decays are relevant, and how BABAR gathers the necessary data. Specifically, they present the analysis of B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0} decays in a sample of 465 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B}. ... continued below

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239 pages

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Osipenkov, Ilya Leonidovich & /UC, Berkeley December 11, 2009.

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The BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider is located at the Stanford Linear Accelerator Center. It has been gathering data on the {Upsilon}(4S) resonance from 2000 until 2007 with the primary objective of studying CP violation in B-meson decays. In this thesis they provide a theoretical overview of how CP violation arises in the context of the Standard Model, why B decays are relevant, and how BABAR gathers the necessary data. Specifically, they present the analysis of B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0} decays in a sample of 465 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B}. They measure the corresponding branching fraction {Beta} = (0.92 {+-} 0.32(stat.) {+-} 0.14(syst.)) x 10{sup -6} and the longitudinal polarization fraction f{sub L} = 0.75{sub -0.14}{sup +0.11}(stat.) {+-} 0.04(syst.). The evidence for the B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0} signal has a significance of 3.1 standard deviations ({sigma}), when the systematic uncertainties are included. There is insufficient evidence for B decays into similar modes and the corresponding upper limits are determined to be {Beta}{sub {rho}{sup 0}f{sub 0}} < 0.34 x 10{sup -6}, {Beta}{sub f{sub 0}f{sub 0}} < 0.16 x 10{sup -6}, {Beta}{sub {rho}{sup 0}{pi}{sup +}{pi}{sup -}} < 8.7 x 10{sup -6}, B{sub {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -}} < 21.1 x 10{sup -6} at the 90% Confidence Level (CL). They also investigate the proper-time dependence of the longitudinal component in the decay and measure the Cp-violating coefficients S{sub L} = 0.3 {+-} 0.7(stat.) {+-} 0.2(syst.) and C{sub L} = 0.2 {+-} 0.8(stat.) {+-} 0.3(syst.). By combining these results with other measurements from the B {yields} {rho}{rho} processes and performing an Isospin Analysis, they are able to restrict the unitarity angle {alpha} as well as its uncertainty due to penguin contributions, {Delta}{alpha}. Namely, {alpha} = (92.4{sub -6.5}{sup +6.0}){sup o} with -1.8{sup o} < {Delta}{alpha} < 6.7{sup o} at 1{sigma} CL.

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239 pages

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  • Report No.: SLAC-R-935
  • Grant Number: AC02-76SF00515
  • Office of Scientific & Technical Information Report Number: 969249
  • Archival Resource Key: ark:/67531/metadc927513

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  • December 11, 2009

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  • Nov. 13, 2016, 7:26 p.m.

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  • Dec. 15, 2016, 3:34 p.m.

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Osipenkov, Ilya Leonidovich & /UC, Berkeley. Time Dependent Analysis of B to rho0rho0 Decays, thesis or dissertation, December 11, 2009; United States. (digital.library.unt.edu/ark:/67531/metadc927513/: accessed August 19, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.