We use a sample of diphoton+dijet events to measure the effective cross section of double parton interactions, which characterizes the area containing the interacting partons in proton-antiproton collisions, and find it to be σeff=19.3±1.4(stat)±7.8(syst) mb. The sample was collected by the D0 detector at the Fermilab Tevatron collider in p¯p collisions at √s=1.96 TeV and corresponds to an integrated luminosity of 8.7 fb−1.Received 17 December 2015DOI:https://doi.org/10.1103/PhysRevD.93.052008© 2016 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasNucleon-nucleon interactionsPhoton, lepton & quark productionQuark & gluon jetsParticles & Fields