Combining QED and QCD transverse-momentum resummation for Z boson production at hadron colliders

TL;DR

This paper develops a combined resummation framework for QED and QCD effects in the transverse momentum distribution of Z bosons at hadron colliders, improving precision for LHC and Tevatron analyses.

Contribution

It introduces an analytic resummation method that simultaneously accounts for QED and QCD corrections up to high logarithmic accuracy in Z boson production.

Findings

QED corrections significantly impact the $q_T$ distribution.

The combined resummation reduces theoretical uncertainties.

Numerical results demonstrate the importance of including QED effects.

Abstract

We consider the transverse-momentum ($q_T$) distribution of $Z$ bosons produced in hadronic collisions. At small values of $q_T$, we perform the analytic resummation of the logarithmically enhanced QED contributions up to next-to-leading logarithmic accuracy, including the mixed QCD-QED contributions at leading logarithmic accuracy. Resummed results are consistently matched with the next-to-leading fixed-order results (i.e. $\mathcal{O}(\alpha^2)$) at small, intermediate and large values of $q_T$. We combine the QED corrections with the known QCD results at next-to-next-to-leading order ($\mathcal{O}(\alpha_S^2)$) and next-to-next-to-leading logarithmic accuracy. We show numerical results at LHC and Tevatron energies, studying the impact of the QED corrections and providing an estimate of the corresponding perturbative uncertainty. Our analytic results for the combined QED and QCD resummation, obtained through an extension of the $q_T$ resummation formalism in QCD, are valid for the production of generic neutral and colourless high-mass systems in hadronic collision.