Measurements of double parton scattering in proton-proton collisions provide insight
into the structure and long-range low-momentum scale interactions of the proton. In this
talk we present a measurement of the double-parton scattering contribution to
four-lepton events at √s=8 TeV. An artificial neural net is used to optimise the analysis
and an upper limit on the double-parton scattering fraction is set at 0.042, which
corresponds to an effective cross section of 1mb. The data are compared to a wide
variety of predictions from Monte Carlo event generators.