Bound-state effects on kinematical distributions of top quarks at hadron colliders

Abstract

First we present a theoretical framework to compute the fully differential cross sections for the top-quark productions and their subsequent decays at hadron colliders, incorporating the bound-state effects which are important in the $ t\bar{t} $ threshold region. We include the bound-state effects such that the cross sections are correct in the LO approximation both in the threshold and high-energy regions. Then, based on this framework we compute various kinematical distributions of top quarks as well as of their decay products at the LHC, by means of Monte-Carlo event-generation. These are compared with the corresponding predictions based on conventional perturbative QCD. In particular, we find a characteristic bound-state effect on the $ \left( {b{W^{+} }} \right){ - }\left( {\bar{b}{W^{-} }} \right) $ double-invariant-mass distribution, which is deformed to the lower invariant-mass side in a correlated manner.