High-precision differential predictions for top-quark pairs at the LHC

TL;DR

This paper provides the first complete NNLO QCD predictions for differential distributions in top-quark pair production at the LHC, improving theoretical accuracy and aiding new physics searches.

Contribution

It delivers the first fully differential NNLO QCD calculations for top-quark pairs at the LHC, with no approximations beyond fixed-order truncation.

Findings

NNLO corrections improve agreement with LHC measurements

Invariant mass distribution shape is stable beyond NLO

Results aid in parton distribution functions and fundamental parameter determinations

Abstract

We present the first complete next-to-next-to-leading order (NNLO) QCD predictions for differential distributions in the top-quark pair production process at the LHC. Our results are derived from a fully differential partonic Monte Carlo calculation with stable top quarks which involves no approximations beyond the fixed-order truncation of the perturbation series. The NNLO corrections improve the agreement between existing LHC measurements [V. Khachatryan et al. (CMS Collaboration), Eur. Phys. J. C 75, 542 (2015)] and standard model predictions for the top-quark transverse momentum distribution, thus helping alleviate one long-standing discrepancy. The shape of the top-quark pair invariant mass distribution turns out to be stable with respect to radiative corrections beyond NLO which increases the value of this observable as a place to search for physics beyond the standard model. The results presented here provide essential input for parton distribution function fits, implementation of higher-order effects in Monte Carlo generators as well as top-quark mass and strong coupling determination.