Interactions of heavy quarks, in particular, of top quarks, with electroweak gauge bosons are expected to be very sensitive to new physics effects related to electroweak symmetry breaking. These interactions are described by the so-called static form factors, which include anomalous magnetic moments and the effective weak charges. We compute the second-order QCD corrections to these static form factors, which turn out to be sizable and need to be taken into account in searches for new anomalous coupling effects.

• Received 29 September 2005

DOI:https://doi.org/10.1103/PhysRevLett.95.261802