Top Production in Hadron–hadron Collisions and Anomalous Top–gluon Couplings

We discuss the influence of anomalous tt̄G couplings on total and differential tt̄ production cross sections in hadron–hadron collisions. We study in detail the effects of a chromoelectric and a chromomagnetic dipole moment, d′t and μ ′ t, of the top quark. In the d′t–μ ′ t plane, we find a whole region where the anomalous couplings give a zero net contribution to the total top production rate. In differential cross sections, the anomalous moments have to be quite sizable to give measurable effects. We estimate the values of d′t and μ ′ t which are allowed by the present Tevatron experimental results on top production. A chromoelectric dipole moment of the top violates CP invariance. We discuss a simple CP–odd observable which allows for a direct search for CP violation in top production. Submitted to Phys. Rev. D