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

TL;DR

This paper develops a theoretical framework to incorporate bound-state effects in top-quark production at hadron colliders, improving predictions of kinematical distributions near the threshold region.

Contribution

It introduces a method to include bound-state effects in differential cross sections, enhancing accuracy in both threshold and high-energy regions for top-quark production.

Findings

Bound-state effects deform the double-invariant-mass distribution towards lower masses.

The framework accurately reproduces cross sections in the threshold and high-energy regions.

Monte Carlo simulations reveal characteristic bound-state signatures in top decay products.

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 (bW^+)-(\bar{b}W^-) double-invariant-mass distribution, which is deformed to the lower invariant-mass side in a correlated manner.