QCD Tests from Tau Decays

Abstract

The total $\tau$ hadronic width can be accurately calculated using analyticity and the operator product expansion. The theoretical analysis of this observable is updated to include all available perturbative and non-perturbative corrections. The experimental determination of ${\alpha }_s(M_{\tau }^2)$ and its actual uncertainties are discussed.

16 pages, latex, 3 Postscript figures, uses sprocl.sty, Invited Talk at the 20th Johns Hopkins Workshop --Non Perturbative Particle Theory & Experimental tests-- (Heidelberg, 27-29 June 1996)