Measurement of four-jet production in proton-proton collisions at sqrt(s) = 7 TeV and UE tunes and double parton scattering

Using the ''Rivet" and ''Professor" framework, we construct a new PYTHIA 6 tune using the CTEQ6L1 PDF and two new PYTHIA 8 UE tunes (one using CTEQ6L1 and one using the HERAPDF1.5LO). By simultaneously fitting CDF data from collisions at 300 GeV, 900 GeV, and 1.96 TeV together with CMS data for pp collisions at 7 TeV, we test the Underlying Event (UE) models and constrain their parameters, allowing for more precise predictions at 13 TeV and 14 TeV. The consistency of these new tunes with measurements of double-parton scattering (DPS) is also investigated. DPS-based tunes are also extracted, relying on differential cross sections as a function of correlation observables, for the production of exactly four jets in proton-proton collisions. From this measurement it is found that the addition of parton showers to fixed-order matrix element calculations describe the measured differential cross sections in only some regions of phase space and that including a contribution from double parton scattering in the models brings the predictions closer to the data.