Update of the electromagnetic effective coupling constant $\alpha (M_Z^2)$

Abstract

We recalculate the hadronic contribution to the effective electromagnetic coupling constant $\alpha (M_Z^2)$ using quasi-analytical approximations for the cross-section of $e^{+}{e}^{-}\to hadrons$ proposed earlier by one of the authors(N.V.K.,Mod.Phys.Lett.A9(1994)2825). We find that ${\alpha }^{-1}(M_Z^2)=128.98\pm 0.06$.

Comments: Latex, 9 pages