W mass and Leptonic Z-decays in the NMSSM

Abstract

We study a subset of electroweak-precision observables consisting of $M_W$, $\sin^2\theta_{{\tiny eff}}^{\tau}$, $BR(Z\to\tau^+\tau^-)$ and $\Gamma(Z\to\tau^+\tau^-)/\Gamma(Z\to e^+e^-)-1$ (characterizing leptonic $Z$-decays) in the context of the NMSSM. After a brief review of common MSSM-NMSSM effects, e.g. for $\Gamma(Z\to\tau^+\tau^-)/\Gamma(Z\to e^+e^-)-1$, which has been little discussed, even in the MSSM), specific NMSSM scenarios are studied, with the result that the NMSSM, considering existing constraints on its spectrum, is essentially consistent with available measurements, given the current accuracy.