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 $W + n$-jetproductionattheLHC\mathrm{.}Wecomputetheratioofcrosssectionsfor$W + n$-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, $H_T^{\mathrm{j}\mathrm{e}\mathrm{t}\mathrm{s}}$; 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 $H_T^{\mathrm{j}\mathrm{e}\mathrm{t}\mathrm{s}}$ 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.