$b \to s γ$ Decay and Right-handed Top-bottom Charged Current

Abstract

We introduce an anomalous top quark coupling (right-handed current) into Standard Model Lagrangian. Based on this, a more complete calculation of $b \to sγ$ decay including leading log QCD corrections from $m_{top}$ to $M_W$ in addition to corrections from $M_{W}$ to $m_b$ is given. The inclusive decay rate is found to be suppressed comparing with the case without QCD running from $m_t$ to $M_W$ except at the time of small values of $|f_R^{tb}|$. e.g. when $f_R^{tb}=-0.08$, it is only $1/10$ of the value given before. As $|f_R^{tb}|$ goes smaller, this contribution is an enhancement like standard model case. From the newly experiment of CLEO Collaboration, strict restrictions to parameters of this top-bottom quark coupling are found.