$\alpha_s(M_Z^2)$ and $R_b$ discrepancy with nonuniversal interactions

Abstract

We implement global fits to LEP data with the \non interactions. Consistent $R_b$ with experimental value and consistent $\as(M_Z^2)$ with that from low energy experiments are obtained. We also find that the $\xx$ is better than the Standard Model. And we argue that other kinds of new physics are needed to explain the difference between the values of $\as(M_Z^2)$ from low energy experiments and from the 3-jet ratio.