Measurement of the 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 has been measured by the ATLAS detector at the LHC. The analyzed dataset corresponds to an integrated luminosity of 36 pb$^{-1}$. The process under study is the production of a $W$ boson in association with exactly two jets. $W$ boson decays in either the electron or muon channel. The fraction of double parton scattering events was found to be 0.08$\pm$0.01(stat.)$\pm$0.02(syst.) for jets with transverse momentum $p_{\rm T}$ $>$ 20 GeV and rapidity $|{y}|$ $<$ 2.8. The double parton scattering scaling factor $\sigma_{\rm{eff}}$ was evaluated to 15$\pm$3(stat.)$^{+5}_{-3}$(syst.) mb.