Measurement of the cross section for the production of a W boson in association with b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

TL;DR

This paper reports a measurement of the W boson production cross section with b-jets in proton-proton collisions at 7 TeV using ATLAS data, providing experimental results compared with QCD predictions.

Contribution

First measurement of W+b-jet cross section at 7 TeV with detailed comparison to NLO QCD calculations.

Findings

Measured cross section: 10.2 +/- 1.9 (stat) +/- 2.6 (syst) pb

Results are consistent with NLO QCD predictions within uncertainties

Analysis used secondary vertex b-jet identification with anti-kt jets

Abstract

A measurement is presented of the cross section for the production of a W boson with one or two jets, of which at least one must be a b-jet, in pp collisions at sqrt(s)=7 TeV. Production via top decay is not included in the signal definition. The measurement is based on 35 pb^-1 of data collected with the ATLAS detector at the LHC. The W+b-jet cross section is defined for jets reconstructed with the anti-kt clustering algorithm with transverse momentum above 25 GeV and rapidity within +/-2.1. The b-jets are identified by reconstructing secondary vertices. The fiducial cross section is measured both for the electron and muon decay channel of the W boson and is found to be 10.2 +/- 1.9 (stat) +/- 2.6 (syst) pb for one lepton flavour. The results are compared with next-to-leading order QCD calculations, which predict a cross section smaller than, though consistent with, the measured value.