1108.4908 (ATLAS Collaboration)

A measurement of the ratio of the W and Z cross sections with exactly
one associated jet in pp collisions at sqrt(s) = 7 TeV with ATLAS    [PDF]

ATLAS Collaboration

The ratio of production cross sections of the W and Z bosons with exactly one
associated jet is presented as a function of jet transverse momentum threshold.
The measurement has been designed to maximise cancellation of experimental and
theoretical uncertainties, and is reported both within a particle-level
kinematic range corresponding to the detector acceptance and as a total
cross-section ratio. Results are obtained with the ATLAS detector at the LHC in
pp collisions at a centre-of-mass energy of 7 TeV using an integrated
luminosity of 33 pb^-1. The results are compared with perturbative
leading-order, leading-log, and next-to-leading-order QCD predictions, and are
found to agree within experimental and theoretical uncertainties. The ratio is
measured for events with a single jet with p_T > 30 GeV to be 8.73 +/- 0.30
(stat) +/- 0.40 (syst) in the electron channel, and $ 8.49 +/- 0.23 (stat) +/-
0.33 (syst) in the muon channel.

View original: http://arxiv.org/abs/1108.4908