Test of the Chiral Structure and FCNC in the Quark Sector by Radiative B Meson Decays

Abstract

We study the effects of a vector-like SU(2) quark doublet as a fourth generation. In this model we examine the chiral structure and the FCNC in the quark sector by using radiative B meson decays in the allowed region for parameters from Rb = Γqq/Γ had . We compute the ratio R = Br (b → dγ)/ Br (b → sγ) in the model which realizes a different chiral structure as well as FCNC. The constraints have been extracted from the experimental results of B meson decays, the T new parameter of oblique corrections and Rb. Under the natural assumption that the violation of the V - A structure in the light-quark sector is small, we can determine the allowed region for most of the mixings parameters and the vector-like quark masses. We show that there will be significant deviations in R from the SM prediction due to the FCNC's and the violation of the V - A structure.