Chromomagnetic dipole moment of the top quark revisited

We study the complete one-loop contributions to the chromagnetic dipole moment Delta k of the top quark in the standard model, two Higgs doublet models, topcolor assisted technicolor models, 331 models and extended models with a single extra dimension. We find that the SM predicts Delta k =-0.056 and the predictions of the other models are also consistent with the constraints imposed on Delta k by low-energy precision measurements.