2001/08/31 by G. Calderon, G. CALDERÓN, G. Lopez Castro +1
Physics and Astronomy · #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #Quantum and Classical Electrodynamics #hep-ph
paper · pdf · doi:10.1142/s0217751x08041578
published as Int.J.Mod.Phys.A23:3525-3533,2008 · 10 pages, published version
openalex publication_date 2008/09/10 · arxiv created 2008/10/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
In the Standard Model, the top quark decay width Γ t is computed from the exclusive t → bW decay. We argue in favor of using the three body decays [Formula: see text] to compute Γ t as a sum over these exclusive modes. As dictated by the S-matrix theory, these three body decays of the top quark involve only asymptotic states and incorporate the width of the W boson resonance in a natural way. The convolution formula commonly used to include the finite width effects is found to be valid, in the general case, when the intermediate resonance couples to a conserved current (limit of massless fermions in the case of W bosons). The relation Γ t = Γ(t → bW) is recovered by taking the limit of massless fermions followed by the W boson narrow width approximation. Although both calculations of Γ t are different at the formal level, their results would differ only by tiny effects induced by light fermion masses and higher-order radiative corrections.