Top Quark Pair Production at Threshold: Complete Next-to-next-to-leading Order Relativistic Corrections

Abstract

The complete next-to-next-to-leading order (i.e. $O(v^2)$, $O(v α_s)$ and $O(α_s^2)$) relativistic corrections to the total photon mediated $t\bar t$ production cross section at threshold are presented in the framework of nonrelativistic quantum chromodynamics. The results are obtained using semi-analytic methods and ``direct matching''. The size of the next-to-next-to-leading order relativistic corrections is found to be comparable to the size of the next-to-leading order ones.

Figures (1)

• Figure 1: (a) The total normalized photon-mediated $t\bar{t}$ cross section at LO (dotted lines), NLO (dashed lines) and NNLO (solid lines) for the soft scales $\mu_{\rm soft}=50$ (upper lines), $75$ and $100$ GeV (lower lines). (b) The NNLO cross section for $\alpha_s(M_z)=0.115$ (solid line), $0.118$ (dashed line) and $0.121$ (dotted line). More details and the other parameters are given in the text.