Determinação da distribuição de glúons nuclear na fotoprodução de quarkonium no RHIC e LHC

Abstract

The hadronic structure is investigated at high energies through scattering processes. As the previous experiments were not able to constrain the nuclear gluon distribution, we propose an alternative to probe this distribution in the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC). We analyze ultraperipheral heavy ion collisions and study the photoproduction of vector mesons considering the collinear formalism, which implies that the cross section is proportional to the square of the gluon distribution. In this thesis we study this process using different parameterizations for the nuclear gluons distribution. We calculate the integrated cross section and the rapidity distribution for the processes AA → V AA(V = J/ , ) to RHIC and LHC energies and different nuclei. We verify that these observables are useful to constrain the nuclear effects in the gluon distribution. A comparison with recent PHENIX data for the coherent J/ production is presented, demonstrating that the experimental analysis of this process is feasible. Our main conclusion is that the study of quarkonium photoproduction can be used to determine the energy behavior and the magnitude of the nuclear effects in the gluon distribution.