Produção de partículas em colisões hadrônicas para baixas e altas multiplicidades

Abstract

Describing the structure of the proton in the regions reached by hadronic collisions at high center-of-mass energies is still a open question. It is known that in these regions the proton is overpopulated by gluons and, therefore, is characterized as a highly dense or saturated medium. It is also in this region that the formation of a new state of matter called Color Glass Condesate (CGC) is expected. In this sense, one question is whether (or how many of) the nonlinear effects predicted by the CGC are identifiable at the LHC. The multiplicity of particles produced in a hadronic collision presents itself as an observable sensitive to the behavior of gluons and, therefore, a means of investigating this and other problems. On the other hand, the description of current data using a unified approach that achieves low and high multiplicity remains a challenge. Also, different experimental collaborations identified that the production of certain final states, in proton-proton collisions, present a modification in the behavior of high multiplicity events in relation to the case of minimum bias. Therefore, the guiding question of the studies presented here is whether this modification results from initial or final state effects, or both. Therefore, a systematic study of particle production in low and high multiplicity events using the CGC formalism will be performed. With this, the intention is to contribute to the advancement of the treatment of the particle production in the frontal and ultra frontal region for the different values of multiplicities and to obtain predictions that can be compared with the experimental data of the LHC, as well as to propose observables that allow to univocally demonstrate the presence of nonlinear effects in the QCD dynamics.