Top-pair production at hadron colliders with next-to-next-to-leading logarithmic soft-gluon resummation

TL;DR

This paper advances theoretical predictions for top-antitop production at hadron colliders by implementing NNLL soft-gluon resummation, reducing uncertainties and aligning well with experimental data, highlighting the need for full NNLO calculations for further precision.

Contribution

It provides the first comprehensive NNLL resummation of soft-gluon effects for top-pair production, improving the accuracy of cross-section predictions at hadron colliders.

Findings

NNLL resummation slightly reduces theoretical uncertainties.

Predictions agree with Tevatron and LHC measurements.

Full NNLO corrections are needed for further improvements.

Abstract

Incorporating all recent theoretical advances, we resum soft-gluon corrections to the total $t\bar t$ cross-section at hadron colliders at the next-to-next-to-leading logarithmic (NNLL) order. We perform the resummation in the well established framework of Mellin $N$-space resummation. We exhaustively study the sources of systematic uncertainty like renormalization and factorization scale variation, power suppressed effects and missing two- and higher-loop corrections. The inclusion of soft-gluon resummation at NNLL brings only a minor decrease in the perturbative uncertainty with respect to the NLL approximation, and a small shift in the central value, consistent with the quoted uncertainties. These numerical predictions agree with the currently available measurements from the Tevatron and LHC and have uncertainty of similar size. We conclude that significant improvements in the $t\bar t$ cross-sections can potentially be expected only upon inclusion of the complete NNLO corrections.