Constraints on the Left-Right Symmetric Model from $b\to s\gamma$

Abstract

The recent observation by the CLEO Collaboration of the inclusive decay $b\to s\gamma$ with a branching fraction consistent with the expectations of the Standard Model is used to constrain the parameter space of the Left-Right Symmetric Model. Two scenarios are considered: ($i$) equal left- and right- handed Cabibbo-Kobayashi-Maskawa mixing matrices, $V_L=V_R (~{\rm or}~V_R^*)$ and ($ii$) the Gronau-Wakaizumi model wherein B-decays proceed only via right-handed currents and $V_L$ and $V_R$ are quite distinct. In the later case the bounds from $b\to s\gamma$ are combined with other constraints leaving a parameter range that is very highly restricted and which implies that this model may soon be completely ruled out by improving data. (To appear in the {\it Proceedings of the 1994 International Workshop on B Physics, Physics Beyond the Standard Model at the B Factory}, Nagoya, Japan, October 26-28, 1994.)