Measurement of hard double-parton interactions in W(→ℓν) + 2-jet events at √s=7 TeV with the ATLAS detector

Abstract

The production of W bosons in association with two jets in proton–proton collisions at a centre-of-mass energy of √s=7 TeV has been analysed for the presence of double-parton interactions using data corresponding to an integrated luminosity of 36 pb[superscript −1], collected with the ATLAS detector at the Large Hadron Collider. The fraction of events arising from double-parton interactions, f[superscript (D) over subscript DP], has been measured through the p[subscript T] balance between the two jets and amounts to f[superscript (D) over subscript DP] = 0.08 ± 0.01 (stat.) ± 0.02 (sys.) for jets with transverse momentum p[subscript T] > 20 GeV and rapidity |y| < 2.8. This corresponds to a measurement of the effective area parameter for hard double-parton interactions of σ[subscript eff] = 15 ± 3 (stat.) [superscript +5 over subscript −3] (sys.) mb.