Full one-loop renormalization of the ratio of neutral and charged current Fermi constants in supersymmetric extensions of the standard model

We present an updated numerical analysis of the complete one-loop radiative corrections to the ρ{variant} parameter, defined as the ratio of the neutral and charged current over-all strengths at zero momentum transfer, in the context of supersymmetric extensions of the standard model of strong and electroweak interactions. We choose a specific renormalization framework, in which neutrino-electron scattering is a fundamental ingredient, and we take into account all possible supersymmetric process-dependent contributions, apart from the universal ones. Contrary to usual claims, we find that the former contributions may well be as important as the latter and of either sign. To the extent that for a fairly broad range of sparticle masses the entire supersymmetric correction to ρ{variant} is driven to negative values of order 10-3, thus reversing the sign of the maximal universal contributions. We also comment on the implications of this fact on the determination of the upper bound on the quark mass obtained from precise measurements of the ρ{variant} parameter. © 1991.