Rare decays in BaBar: Search for neutral B meson going to lepton-antilepton decays and measurement of CP asymmetry in inclusive B meson going to X(s) meson-gamma decays

• Main Author: Salvati, Emmanuele
• Language: ENG
• Published: ScholarWorks@UMass Amherst 2010
• Subjects: Particle physics
• Online Access: https://scholarworks.umass.edu/dissertations/AAI3397745

The purpose of this thesis is the study of rare decays with the BABAR detector. In the first part we present the study of the leptonic decays B0 → e +e-, B0 → μ +μ- and B0 → e±μ∓, based on a dataset corresponding to (383.6 ± 4.2) × 106 BB¯ pairs. We do not find evidence of any of the three decay modes, and obtain upper limit on the branching fractions, at 90% confidence level, of [special characters omitted](B0 → e +e-) < 11.3 × 10-8 , [special characters omitted](B0 → μ+μ -) < 5.2 × 10-8, and [special characters omitted](B0 → e ±μ∓) < 9.2 × 10-8. In the second part we present the measurement of CP asymmetry in rare inclusive B → Xsγ decays on the recoil of fully-reconstructed hadronic B decays, using a dataset corresponding to (465.0 ± 5.1) × 106 BB¯ pairs. We measure a value of ACP = -0.12 ± 0.11 ± 0.03.