A measurement of the underlying event (UE) activity in proton-proton collisions at a centre-of-mass energy of 7 TeV is performed using Drell-Yan events in a data sample corresponding to an integrated luminosity of 2.2 fb⁻¹

Read the paper: QCD-10-037

The measured Drell-Yan production rates, normalised to the production rates in the Z-boson region, show good agreement with the theoretical predictions.