Propriedades das colisões ultracentrais relativísticas em Pb-Pb

Abstract

The matter produced in high-energy collisions of heavy nuclei can be described using relativistic hydrodynamics. Particularly in ultracentral collisions (central overlap between the colliding nuclei), there are observables that may access the thermodynamic properties of this state, such as the increase in the average transverse momentum of charged hadrons as a function of particle multiplicity. We argue that the relative increase in transverse momentum depends on the speed of sound in the Quark-Gluon Plasma. For this study, initial conditions were generated for Au-Au and Pb-Pb collisions, and through their analysis, it is possible to observe that entropy density increases as the collision becomes more central, as the volume becomes constant while entropy continues to rise. By utilizing initial conditions from events with Grad parameters of the JETSCAPE Collaboration, we identified a different behavior in energy density. After meticulous analysis, we concluded that the nucleon width (w) plays a fundamental role in this energy density behavior, consequently influencing the average transverse momentum. Further analysis revealed a novel discovery: sound speeds vary for different species, indicating promising areas for future investigation.