Finite-width effects in top quark production at hadron colliders

Abstract

Production cross sections for $t\overline{t}$ and $t\overline{t}j$ events at hadron colliders are calculated, including finite-width effects and off resonance contributions for the entire decay chain, $t\ensuremath{\rightarrow}\mathrm{bW}\ensuremath{\rightarrow}\mathrm{bl}\ensuremath{\nu},$ for both top quarks. The resulting background rates to a Higgs boson search at the CERN large hadron collider are updated for inclusive $H\ensuremath{\rightarrow}\mathrm{WW}$ studies and for $H\ensuremath{\rightarrow}\ensuremath{\tau}\ensuremath{\tau}$ and $H\ensuremath{\rightarrow}\mathrm{WW}$ decays in weak boson fusion events. The finite-width effects are large, increasing $t\overline{t}(j)$ rates by 20% or more, after typical cuts which are employed for top-background rejection.