Abstract :
We consider image, image and image production (image) mediated by strong flavour-changing neutral interactions within an effective operator framework. We provide total cross sections for Tevatron and LHC, showing explicitly that the six processes can be described in full generality in terms of only two parameters (anomalous couplings) for image plus two for image. In our work we take into account and study in detail the effects of top quark decay. For γt, the inclusion of the top quark decay in the matrix element reveals an striking result: the largest contribution to the final state, e.g. image with image, does not result from image but from on-shell image production with image, being the photon radiated off the top decay products. This contribution, missed in previous literature, increases the signal cross sections by factors ranging between 3 and 6.5.
