Measurement of double parton scattering in W + 2 jets production at $\sqrt{s}$ = 7 TeV with the ATLAS detector

The presence of the double parton scattering in proton-proton collisions at $\sqrt{s}$ = 7 TeV was measured by the ATLAS detector at the LHC. The analyzed dataset was recorded in 2010 and corresponds to an integrated luminosity of 36 pb$^{-1}$. The process under study is the production of a W boson, decaying in electron or muon channel, in association with two jets. The fraction of double parton scattering events is found to be 0.08 $\pm$ 0.01 (stat.) $\pm$ 0.02 (syst.) and the scaling factor $\sigma_{eff}$ is evaluated to be 15 $\pm$ 3 (stat.) $^{+5}_{-3}$ (syst.) mb.