"The production of W bosons in association with two jets in proton-proton collisions at a centre-of-mass energy of root s = 7 TeV has been analysed for the presence of double-parton interactions using data corresponding to an integrated luminosity of 36 pb(-1), collected with the ATLAS detector at the Large Hadron Collider. The fraction of events arising from double-parton interactions, f(DP)((D)), has been measured through the p(T) balance between the two jets and amounts to f(DP)((D)) = 0.08 +\/- 0.01 (stat.) +\/- 0.02 (sys.) for jets with transverse momentum p(T) > 20 GeV and rapidity vertical bar y vertical bar < 2.8. This corresponds to a measurement of the effective area parameter for hard double-parton interactions of sigma(eff) = 15 +\/- 3 (stat.)(-3)(+5) (sys.) mb."
Aad, G., Abajyan, T., Abbott, B., Abdallah, J., Khalek, S.a., Abdelalim, A.a., et al. (2013). Measurement of hard double-parton interactions in W(-> lv) plus 2-jet events at root s=7 TeV with the ATLAS detector. NEW JOURNAL OF PHYSICS, 15, 1-39 [10.1088/1367-2630/15/3/033038].