Extrapolating W-Associated Jet-Production Ratios At The Lhc

Electroweak vector-boson production, accompanied by multiple jets, is an important background to searches for physics beyond the standard model. A precise and quantitative understanding of this process is helpful in constraining deviations from known physics. We study four key ratios in W + n-jet production at the LHC. We compute the ratio of cross sections for W + n- to W + (n - 1)-jet production as a function of the minimum jet transverse momentum. We also study the ratio differentially, as a function of the W-boson transverse momentum; as a function of the scalar sum of the jet transverse energy, H-T(jets); and as a function of certain jet transverse momenta. We show how to use such ratios to extrapolate differential cross sections to W + 6-jet production at next-to-leading order, and we cross-check the method against a direct calculation at leading order. We predict the differential distribution in H-T(jets) for W + 6 jets at next-to-leading order using such an extrapolation. We use the BLACKHAT software library together with SHERPA to perform the computations.