Constraints on left-right symmetric models from the process b rightarrow s γ

In left-right symmetric models, large contributions to the decay amplitude $b \rightarrow s+ \gamma$ can arise from the mixing of the $W_L$ and $W_R$ gauge bosons as well as from the charged Higgs boson. These amplitudes are enhanced by the factor $\mt/\mb$ compared to the contributions in the standard model. We use the recent CLEO results on the radiative $B$ decay to place constraints on the $W_L-W_R$ mixing angle $\zeta$ and the mass of the charged Higgs boson $m_{H^\pm}$. Significant departures from the standard model predictions occur when $|\zeta| > 0.003$ and/or when $m_{H^\pm} < $ a few TeV.