A Measurement of the Ratio of the W + 1 Jet to Z + 1 Jet Cross Sections with ATLAS

TL;DR

This paper measures the ratio of W+1 jet to Z+1 jet production cross sections at 7 TeV using ATLAS data, testing perturbative QCD predictions and aiding new physics searches.

Contribution

It provides the first detailed measurement of the Rjet ratio as a function of jet transverse momentum at the LHC, comparing results with theoretical models.

Findings

The measured Rjet ratio agrees with NLO pQCD predictions.

Results show the ratio's dependence on jet transverse momentum.

Data constrains theoretical models of vector boson plus jet production.

Abstract

The measurement of hadronic activity recoiling against W and Z vector bosons provides an important test of perturbative QCD, as well as a method of searching for new physics in a model independent fashion. We present a study of the cross-section ratio for the production of W and Z gauge bosons in association with exactly one jet Rjet = {\sigma}(W + 1jet)/{\sigma}(Z + 1jet), in pp collisions at \surds = 7 TeV. The study is performed in the electron and muon channels with data collected with the ATLAS detector at the LHC. The ratio Rjet is studied as a function of the cumulative transverse momentum distribution of the jet. This result can be compared to NLO pQCD calculations and the prediction from LO matrix element + parton shower generators.