Measurement of the transverse momentum distribution of Drell-Yan lepton pairs in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector

TL;DR

This paper presents high-precision measurements of the transverse momentum and angular distributions of Drell-Yan lepton pairs in proton-proton collisions at 13 TeV, testing perturbative QCD predictions with improved accuracy.

Contribution

It provides the first detailed measurement of these distributions at 13 TeV, combining electron and muon channels, and compares results with advanced QCD models.

Findings

Resummation-based QCD predictions describe the data within uncertainties.

Measurements reach 0.2% precision at low transverse momentum.

Probes perturbative QCD at higher energy with different initial state compositions.

Abstract

This paper describes precision measurements of the transverse momentum $p_\mathrm{T}^{\ell\ell}$ ($\ell=e,\mu$) and of the angular variable $\phi^{*}_{\eta}$ distributions of Drell-Yan lepton pairs in a mass range of 66-116 GeV. The analysis uses data from 36.1 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13$ TeV collected by the ATLAS experiment at the LHC in 2015 and 2016. Measurements in electron-pair and muon-pair final states are performed in the same fiducial volumes, corrected for detector effects, and combined. Compared to previous measurements in proton-proton collisions at $\sqrt{s}=$7 and 8 TeV, these new measurements probe perturbative QCD at a higher centre-of-mass energy with a different composition of initial states. They reach a precision of 0.2% for the normalized spectra at low values of $p_\mathrm{T}^{\ell\ell}$. The data are compared with different QCD predictions, where it is found that predictions based on resummation approaches can describe the full spectrum within uncertainties.