Top tree amplitudes for higher order calculations

TL;DR

This paper provides compact analytic formulas for tree-level amplitudes involving top-antitop pairs and up to four massless partons, aiding higher-order calculations in top quark production.

Contribution

It introduces new calculations of top pair amplitudes with multiple partons using BCFW recursion, enhancing NNLO correction computations.

Findings

Analytic results for $tar{t}$ with up to four partons.

Amplitudes enable efficient NNLO $tar{t}$ production modeling.

Includes decay correlations for on-shell top quarks.

Abstract

We present compact analytic results for tree-level amplitudes containing a $t \bar{t}$ pair accompanied by up to four massless partons, $t \bar{t}gg$, $t \bar{t}ggg$, $t \bar{t}gggg$, $t \bar{t}q\bar{q}$, $t \bar{t}q\bar{q}g$, $t \bar{t}q\bar{q}gg$ and $t\bar{t}q\bar{q}q^\prime \bar{q}^\prime$. The results, obtained using BCFW on-shell recursion, are based both on previous published results and on the new calculations performed in this paper. These amplitudes are sufficient to calculate the production of a $t\bar{t}$ pair and zero, one, or two light parton jets, with the option to include the tree-level decays $t \to b \nu e^+$ and $\bar{t} \to \bar{b} e^- \bar{\nu}$ efficiently. Our results are part of the NNLO corrections to $t \bar{t}$ production including the decay correlations for on-shell top quarks.