Role of multiparton interactions on J /ψ production in p+p collisions at LHC energies

Abstract

The production mechanism of quarkonia states in hadronic collisions is still to be understood by the scientific community. In high-multiplicity p+p collisions, underlying event observables are of major interest. The multiparton interactions (MPIs) are underlying event observables, in which several interactions occur at the partonic level in a single p+p event. This leads to dependence of particle production on event multiplicity. If the MPI occurs in a harder scale, there will be a correlation between the yield of quarkonia and total charged-particle multiplicity. The ALICE experiment at the LHC in p+p collisions at s=7 and 13 TeV has observed an approximate linear increase of relative J/ψ yield, (dNJ/ψ/dydNJ/ψ/dy), with relative charged-particle multiplicity density, (dNch/dydNch/dy). In our present work, we have performed a comprehensive study of the production of charmonia as a function of charged-particle multiplicity in p+p collisions at LHC energies using the perturbative QCD-inspired multiparton interaction model, pythia8 tune 4C, with and without the color reconnection scheme. A detailed multiplicity and energy-dependent study is performed to understand the effects of MPI on J/ψ production. The ratio of ψ(2S) to J/ψ is also studied as a function of charged-particle multiplicity at LHC energies. © 2018 authors. Published by the American Physical Society.