Supersymmetry and Electroweak Leptonic Observables

We study vertex corrections to the leptonic electroweak observables in the general minimal supersymmetric standard model at $\mathrm{tan}\ensuremath{\beta}\ensuremath{\lesssim}35.$ In particular, we address the question of whether supersymmetry can be responsible for the observed $2\ensuremath{\sigma}$ 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 ${g}_{\ensuremath{\mu}}\ensuremath{-}2$ measurements makes the agreement with experiment slightly better and improves the electroweak fit.