Next-to-leading order QCD corrections to top quark spin correlations at hadron colliders: the reactions $gg\to t\bar{t}(g)$ and $gq(\bar{q})\to t\bar{t}q(\bar{q})$

Abstract

We have computed the cross section for $t\bar{t}$ production by gluon-gluon fusion at next-to-leading order (NLO) in the QCD coupling, keeping the full dependence on the $t\bar{t}$ spins. Furthermore we have determined to the same order the spin dependent cross sections for the processes $g+q(\bar{q})\to t\bar{t}+q(\bar{q})$. Together with our previous results for $q+\bar{q}\to t\bar{t}(g)$ these results allow for predictions, at NLO QCD, of the hadronic production of $t\bar{t}$ pairs in a general spin configuration. As an application we have determined the degree of correlation of the $t$ and $\bar{t}$ spins at NLO, using various spin quantisation axes.

10 pages, 8 figures