Particle Physics Seminar

Radiative penguin decays of B mesons provide a fertile ground for precision tests of the Standard Model. Because such decays must proceed through 1-loop or higher processes in Standard Model perturbation theory, they are quite rare and their amplitudes are particularly susceptible to interference from physics beyond the Standard Model. Within the Standard Model, radiative penguin decays of $B$ mesons provide a method of directly measuring |V_{td} / V_{ts}| which is independent of B_{s} mixing. This talk presents a search for the radiative penguin decays B0 --> rho0 gamma, B+ --> rho+ gamma, and B0 --> omega gamma conducted at the BaBar experiment. This analysis sets 90% confidence upper limits on their branching fractions of
BF(B0 --> rho0 gamma) < 0.4 x 10^{-6}
BF(B+ --> rho+ gamma) < 1.8 x 10^{-6}
BF(B0 --> omega gamma) < 1.0 x 10^{-6}
The ratio of the branching fractions BF(B --> (rho/omega) gamma) and BF(B --> K* gamma) are related to the CKM matrix ratio |V_td / V_ts|. The measurements presented in this thesis analysis a 90% confidence level upper limit of
|V_td / V_ts| < 0.190.