Collaboration, D0 and Bertram, Iain and Borissov, Guennadi and Fox, Harald and Ross, Anthony and Williams, Mark and Ratoff, Peter and Love, Peter and Sopczak, Andre (2011) Azimuthal decorrelations and multiple parton interactions in photon+2 jet and photon+3 jet events in ppbar collisions at sqrt{s}=1.96 TeV. Physical Review D, 83 (5): 052008. ISSN 1550-7998
Abstract
Samples of inclusive photon+2 jet and photon+3 jet events collected by the D0 experiment with an integrated luminosity of about 1fb^-1 in ppbar collisions at sqrt{s}=1.96 TeV are used to measure cross sections as a function of the angle in the plane transverse to the beam direction between the transverse momentum (pT) of the photon+leading jet system (jets are ordered in pT) and pT of the other jet for photon+2 jet, or pT sum of the two other jets for photon+3 jet events. The results are compared to different models of multiple parton interactions (MPI) in the PYTHIA and SHERPA Monte Carlo (MC) generators. The data indicate a contribution from events with double parton (DP) interactions and are well described by predictions provided by the PYTHIA MPI models with pT-ordered showers and by SHERPA with the default MPI model. The photon+2 jet data are also used to determine the fraction of events with DP interactions as a function of the azimuthal angle and as a function of the second jet pT.