On top-pair hadro-production at next-to-next-to-leading order

TL;DR

This paper advances the precision of top quark pair production cross section calculations at NNLO in QCD by combining high-energy limit results with threshold corrections, reducing theoretical uncertainties for collider predictions.

Contribution

It provides new approximate NNLO results across the full kinematic range using k_t-factorization and threshold corrections, offering a valuable check for future complete NNLO computations.

Findings

Residual uncertainty of about 4% at Tevatron

Residual uncertainty of about 5% at LHC

High-energy limit results serve as important validation tools

Abstract

We study the QCD corrections at next-to-next-to-leading order (NNLO) to the cross section for the hadronic pair-production of top quarks. We present new results in the high-energy limit using the well-known framework of k_t-factorization. We combine these findings with the known threshold corrections and present improved approximate NNLO results over the full kinematic range. This approach is employed to quantify the residual theoretical uncertainty of the approximate NNLO results which amounts to about 4% for the Tevatron and 5% for the LHC cross-section predictions. Our analytic results in the high-energy limit will provide an important check on future computations of the complete NNLO cross sections.