Measurements of differential cross sections of Z/gamma*+jets+X events in proton anti-proton collisions at sqrt{s}=1.96 TeV

TL;DR

This paper measures the differential cross sections of Z/gamma*+jets+X events in proton-antiproton collisions at 1.96 TeV, comparing results with perturbative QCD predictions and various event generators, highlighting discrepancies and scale uncertainties.

Contribution

It provides the first detailed differential cross section measurements for Z/gamma*+jets+X at Tevatron energies and evaluates the performance of different theoretical models and event generators.

Findings

Perturbative QCD predictions agree within uncertainties.

Parton-shower generators show shape and normalization discrepancies.

Tree-level matrix element generators describe shapes well but have normalization issues.

Abstract

We present cross section measurements for Z/gamma*+jets+X production, differential in the transverse momenta of the three leading jets. The data sample was collected with the D0 detector at the Fermilab Tevatron proton anti-proton collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of 1 fb-1. Leading and next-to-leading order perturbative QCD predictions are compared with the measurements, and agreement is found within the theoretical and experimental uncertainties. We also make comparisons with the predictions of four event generators. Two parton-shower-based generators show significant shape and normalization differences with respect to the data. In contrast, two generators combining tree-level matrix elements with a parton shower give a reasonable description of the the shapes observed in data, but the predicted normalizations show significant differences with respect to the data, reflecting large scale uncertainties. For specific choices of scales, the normalizations for either generator can be made to agree with the measurements.