Resummed differential cross sections for top-quark pairs at the LHC

TL;DR

This paper develops advanced resummation techniques for differential cross sections in top-quark pair production at the LHC, improving theoretical predictions especially in boosted regimes by combining multiple resummation methods with NLO calculations.

Contribution

It introduces a formalism that simultaneously resums soft and small-mass logarithms at NNLL$'$ accuracy, enhancing the precision of differential cross section predictions across the entire phase space.

Findings

Resummation effects significantly improve agreement with experimental data.

All-orders resummation is crucial for accurate predictions in high-energy tails.

The combined resummation approach outperforms fixed-order and NNLO approximations.

Abstract

We present state of the art resummation predictions for differential cross sections in top-quark pair production at the LHC. They are derived from a formalism which allows the simultaneous resummation of both soft and small-mass logarithms, which endanger the convergence of fixed-order perturbative series in the boosted regime, where the partonic center-of-mass energy is much larger than the mass to the top quark. We combine such a double resummation at NNLL$'$ accuracy with standard soft-gluon resummation at NNLL accuracy and with NLO calculations, so that our results are applicable throughout the whole phase space. We find that the resummation effects on the differential distributions are significant, bringing theoretical predictions into better agreement with experimental data compared to fixed-order calculations. Moreover, such effects are not well described by the NNLO approximation of the resummation formula, especially in the high-energy tails of the distributions, highlighting the importance of all-orders resummation in dedicated studies of boosted top production.