Phenomenological studies of initial state effects and jet quenching in High-Energy Nuclear Collisions at LHC

Abstract

Heavy ion collisions (HICs) are the appropriate tools to study the so-called quark-gluon plasma (QGP). This thesis is focused on the analysis of two types of effects arising in HICs: initial state effects and final state effects. Among the former, there are the nuclear parton distribution functions (nPDFs), whose precise determination is crucial for the correct interpretation of any observable used in HICs. In this thesis a global analysis of nPDFs at next-to-next-to-leading-order in perturbative QCD (pQCD) is performed. Another very interesting issue regarding the initial stage of HICs are the collective phenomena that give rise to the QGP. These are addressed within the string percolation model (SPM). The results obtained in this framework for different observables are compared to available experimental data. Amongst the final state it is worth stressing hard probes, which are observables characterized by a high energy or mass. An analysis of single-inclusive suppression of hard particles at different center of mass energies and centralities in presented. The main result of this work is the extraction of the so-called jet quenching coefficient.