ELECTROWEAK ONE-LOOP CONTRIBUTIONS TO TOP PAIR PRODUCTION IN HADRON COLLIDERS

We give a detailed presentation of the electroweak one-loop contributions to the production mechanisms of top quark pairs, qqBAR --> ttBAR and gg --> ttBAR, for the energy range of future hadron colliders. The full gauge-invariant set of loop diagrams with Higgs, Z0 and W+/- bosons is considered including strong Yukawa couplings. The parton cross sections get sizeable modifications up to 40% and are sensitive to the Higgs boson mass and the Yukawa coupling. Results are also given for the observable hadronic cross section pp --> ttXBAR, where the large corrections at the parton level are substantially reduced to the order of a few percent. For the electroweak Standard Model the maximum contribution is about 7% for a light Higgs boson with M(eta) = 60 GeV. For Higgs bosons with M(eta) > 200 GeV, the electroweak contributions are typically (2-3)%.