Differential cross section measurements for the production of a W boson in association with jets in proton-proton collisions at sqrt(s) = 7 TeV

TL;DR

This paper reports measurements of how often W bosons produced with jets occur in proton-proton collisions at 7 TeV, comparing results with theoretical predictions and identifying areas of agreement and discrepancy.

Contribution

First detailed differential cross section measurements for W+jets production at 7 TeV, with comparisons to multiple theoretical models and calculations.

Findings

Overall good agreement with predictions

Discrepancies at high jet transverse momentum

Discrepancies in azimuthal angle distributions

Abstract

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pt) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 inverse femtobarns. The measured cross sections are compared to predictions from Monte Carlo generators, MADGRAPH + PYTHIA and SHERPA, and to next-to-leading-order calculations from BLACKHAT + SHERPA. The differential cross sections are found to be in agreement with the predictions, apart from the pt distributions of the leading jets at high pt values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.