We compute the /t-->WZb decay rate, in the Standard Model, at the leading order in perturbation theory, with special attention to the effects of the finite widths of the /W and /Z bosons. These effects are extremely important, since the /t-->WZb decay occurs near its kinematical threshold. They increase the value of the decay rate by orders of magnitude near threshold or allow it below the nominal threshold. We discuss a procedure to take into account the finite-width effects and compare the results with previous studies of this decay. Within the Standard Model, for a top quark mass in the range between 170 and 180 GeV, we find BR(t-->WZb)~=2×10-6, which makes the observation at the LHC very difficult if at all possible.
Physics Letters B
- Pub Date:
- March 2001
- High Energy Physics - Phenomenology
- 10 pages, 4 eps figures, LaTeX. Few references added and minor changes in the text. Results unchanged. Final version to appear on PLB