Experimental tests on gauge theories

After a brief review of the main features of the gauge theory of weak interactions, known as SU(2)/sub L/*U(1), the up-to-date experimental situation is presented. In the charged current sector the mu /sup +/ polarization measurement from the reaction nu /sub mu /N to mu /sup + /X gives a general confirmation at large Q/sup 2/ of the gauge nature of the weak interaction. The neutral current weak interaction results from e/sup +/e/sup -/ storage rings and in neutrino quark scattering are reviewed with particular attention to the measurement of the weak strength parameter sin/sup 2/ theta /sub w/. (0 refs).