Supersymmetry and electroweak leptonic observables

We study vertex corrections to the leptonic electroweak observables in the general minimal supersymmetric standard model at tan betaless than or similar to35. In particular, we address the question of whether supersymmetry can be responsible for the observed 2sigma deviation from the standard model prediction in the invisible width of the Z. We find that the presence of a light (around 100 GeV) chargino and sleptons hinted by the g(mu) - 2 measurements makes the agreement with experiment slightly better and improves the electroweak fit.