Resummed corrections to the \rho parameter due to a finite width of the top quark

Abstract

We perform an all-order calculation of the \rho parameter in a simplified framework, where the top propagator can be calculated exactly. Special emphasis is placed on the question of gauge invariance and the treatment of non-perturbative cut-off effects.Comment: 21 pages, 4 figures, 1 table, typos corrected, final version published by Phys. Rev.