What can we learn from the measurement $R_b \equiv Γ(Z\to b \overline{b}) / Γ(Z\to {\rm hadrons})$?

Abstract

We examine the effect of new physics on the $R_b \equiv Γ(Z\rightarrow \bar{b}b)/Γ(Z\rightarrow {\rm hadrons})$. Conditions for large contributions are derived.