Azimuthal correlations in photoproduction and deep inelastic ep scattering at HERA
Document Type
Article
Publication Date
12-16-2021
Abstract
Collective behaviour of final-state hadrons, and multiparton interactions are studied in high-multiplicity ep scattering at a centre-of-mass energy root s = 318 GeV with the ZEUS detector at HERA. Two- and four-particle azimuthal correlations, as well as multiplicity, transverse momentum, and pseudorapidity distributions for charged-particle multiplicities N-ch >= 20 are measured. The dependence of two-particle correlations on the virtuality of the exchanged photon shows a clear transition from photoproduction to neutral current deep inelastic scattering. For the multiplicities studied, neither the measurements in photoproduction processes nor those in neutral current deep inelastic scattering indicate significant collective behaviour of the kind observed in high-multiplicity hadronic collisions at RHIC and the LHC. Comparisons of PYTHIA predictions with the measurements in photoproduction strongly indicate the presence of multiparton interactions from hadronic fluctuations of the exchanged photon.
Keywords
Collective flow, Lepton-Nucleon Scattering (experiments), Particle correlations and fluctuations, Quark gluon plasma
Funders
Istituto Nazionale di Fisica Nucleare (INFN),Federal Ministry of Education & Research (BMBF) [Grant No: 05 H09PDF & 05h09GUF],UK Research & Innovation (UKRI) Science & Technology Facilities Council (STFC),Natural Sciences and Engineering Research Council of Canada (NSERC),German Research Foundation (DFG) European Commission [Grant No: SFB 1225],German Research Foundation (DFG) [Grant No: SFB 676],Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT),Israel Science Foundation,Office of Nuclear Physics within the U.S. DOE Office of Science,Polish National Science Centre (NCN) [Grant No: DEC-2014/13/B/ST2/02486],Universiti Malaya [Grant No: UM.C/625/1/HIR/149, RU006-2013, RP012A-13AFR & RP012B-13AFR],Ministry of Education, Malaysia [Grant No: ER004-2012A]
Publication Title
Journal of High Energy Physics
Issue
12
Publisher
Springer
Publisher Location
ONE NEW YORK PLAZA, SUITE 4600, NEW YORK, NY, UNITED STATES