Heavy top renormalon contribution to fermion propagators

Abstract

We study resummed perturbative contributions due to a heavy top-quark. These renormalon contributions are evaluated for fermion propagators. Results for the top-quark width are given. Estimates of non-perturbative uncertainties are made on the \rho-parameter using different schemes of dealing with the Landau-pole. For the physical top-quark mass the effects are negligible.

Comments: 30 pages, 14 figures, 1 table; v2: Ref.19 added, typos corrected, final version published in PRD