SUPERSYMMETRY SIGNALS IN ELECTROWEAK PRECISION TESTS AT LEP

With some of the superpartners in a favourable (and small) range of masses and couplings, easily explorable at LEP II, the precision measurements at LEP I could already give a signal interpretable as indirect evidence for supersymmetry, even without knowing the top quark mass. A Z-wave-function renormalization effect due to virtual gaugino-higgsinos might systematically lower all the Z-widths without affecting the asymmetries. This would best show up in a low value of the parameter epsilon-3 (as defined by Altarelli and Barbieri), which we compute, together with epsilson-1 and epsilon-2, in the minimal supersymmetric standard model with all one loop effects included. As a byproduct, we give explicit expressions for the epsilon-parameters in terms of one loop unrenormalized Green functions, applicable to any SU (2) x U (1) gauge theory with an arbitrary number of Higgs doublets.