Lepton Universality

Abstract

The Standard Model requires the three known leptonic families to have identical couplings to the gauge bosons. The present experimental tests on lepton universality are reviewed, both for the charged and neutral current sectors. Our knowledge about the Lorentz structure of the $l^{-}\to {\nu }_l{l}^{\prime -}{\bar{\nu }}_{l^{\prime }}$ transition amplitudes is also discussed.

Comments: 21 pages, latex, 6 Postscript figures, Lectures at the Cargese'96 School --Masses of Fundamental Particles-- (Cargese, Corsica, 5-17 August 1996