Theoretical Expectations in Radiative Top Decays

TL;DR

This paper reviews Standard Model predictions for rare three-body top quark decays, highlighting their extremely low branching ratios for Z and H final states and the comparatively higher rates for g and gamma channels.

Contribution

It provides theoretical estimates of top quark decay branching ratios into various three-body final states within the Standard Model.

Findings

Branching ratios for Z and H final states are about 10^{-7}.

Decays to g and gamma are suppressed only by coupling constants.

Z and H decay modes are effectively invisible at Tevatron Run II.

Abstract

We summarize the Standard Model predictions for the three-body decays of the top quark t->WbX, where X = Z,H,g or gamma. Because of strong phase space suppression, we find that the branching ratios for the Z and H final states are of order a few times 10^{-7}, rendering them invisible at Tevatron Run II. On the other hand, the decays to g and gamma are suppressed only by the expected factor of alpha_s or alpha_{em}.