A measurement of the production of jets in association with a W boson in proton-antiproton collisions at the Tevatron using data collected with the CDF experiment

A measurement of the differential pp W+ > n jets production cross-section with respect to a range of different jet kinematic variables is presented. The W is required to decay leptonically to an electron and neutrino, and the kinematics of the decay products are restricted such that the electron Px > 20 GeV, electron 77 30 GeV and the W transverse mass > 20 GeV/c2. Jets are defined using the CDF JetClu cone algorithm with a radius of R = 0.4, requiring 77jet 15 GeV. The jet energies are corrected individually such that they are on average equal to the energy of the hadrons within the jet, with additional correction factors being applied to account for the impact of detector resolution on the jet spectra. The differential cross-section is measured with respect to the first, second, third and fourth jet Ex spectra, the separation in R and the invariant mass of the two leading jets. In addition, the jet Ex measurements can be integrated to form W+ > n Jets cross-section measurements for 1,2,3 and 4 jets with a range of minimum jet Ex requirements, the lowest being 15 GeV. These cross-section results are compared to Enhanced Leading Order (ELO) W + jets theoretical predictions and predictions made using the leading order CKKW and MLM matching prescriptions. The ELO predictions are not suited to describing the absolute rate of W + jet production, but display success in reproducing certain relative rates, dependent on the choice of renormalisation scale. The comparisons with matching prescriptions indicate that these new approaches could be used successfully to improve W + Jets LO predictions.