PT Journal AU ATLAS Collaboration (Aad, Gea Amoros, G Cabrera Urban, S Castillo Gimenez, V Costa, MJ Escobar, C Ferrer, A Fuster, J Garcia, C Gonzalez de la Hoz, S Hernandez Jimenez, Y Higon-Rodriguez, E Irles Quiles, A Kaci, M Lacasta, C Lacuesta, VR Marti-Garcia, S Mi̱ano, M Mitsou, VA Moles-Valls, R Moreno Llacer, M Oliver Garcia, E Perez Garcia-Esta̱, MT Ros, E Salt, J Solans, CA Soldevila, U Sanchez, J Torro Pastor, E Valladolid Gallego, E Valls Ferrer, JA Villaplana Perez, M Vos, M Wildauer, A TI Measurement of the production cross section for W-bosons in association with jets in pp collisions at root s=7 TeV with the ATLAS detector SO Physics Letters B JI Phys. Lett. B PY 2011 BP 325 EP 345 VL 698 IS 5 DI 10.1016/j.physletb.2011.03.012 LA English DE W-boson; Jets; ATLAS; LHC; Proton-proton; 7 TeV AB This Letter reports on a first measurement of the inclusive W + jets cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC, with the ATLAS detector. Cross sections, in both the electron and muon decay modes of the W-boson, are presented as a function of jet multiplicity and of the transverse momentum of the leading and next-to-leading jets in the event. Measurements are also presented of the ratio of cross sections sigma (W + >= n)/sigma(W + >= n Р1) for inclusive jet multiplicities n = 1-4. The results, based on an integrated luminosity of 1.3 pb(-1), have been corrected for all known detector effects and are quoted in a limited and well-defined range of jet and lepton kinematics. The measured cross sections are compared to particle-level predictions based on perturbative QCD. Next-to-leading order calculations, studied here for n <= 2, are found in good agreement with the data. Leading-order multiparton event generators, normalized to the NNLO total cross section, describe the data well for all measured jet multiplicities. ER