Strangeness and charm in quark-gluon hadronization

Abstract

This dissertation presents a theoretical study of soft hadron production in relativistic heavy-ion collisions. We explore the principles governing the hadronization of the expanding QGP fireball, and to understand its properties. Much of the ongoing effort is to demonstrate the validity of a QGP hadronization model which describes the particle production data accurately. We begin with a centrality study of multistrange hadrons from Au-Au collisions at 62.4 GeV at RHIC. We show that the statistical hadronization model (SHM) well describes particle production in QGP hadronization. For all centralities, the physical properties are compatible with the earlier proposed critical hadronization pressure suggesting universal hadronization conditions of QGP. Heavy-ion collisions at LHC present a new challenge for SHM in describing particle production at TeV energy scales. We show that the chemical non-equilibrium model gives a good description of the hadron production in Pb--Pb collisions at 2.76 TeV consistently as a function of centrality. Moreover, the model parameters assume expected values suggested by previous studies at lower energies. The quark-gluon plasma fireball hadronizes at the same universal hadronization conditions, that is a common critical pressure, entropy and energy density. At LHC energies, a significant amount of charm is expected to be produced and it is therefore crucial to incorporate charm into the present description of particle production. We present an upgraded SHARE with CHARM program, that quantifies the effect of charm on the yield of lighter hadrons and physical properties of the hadronizing fireball. In addition to light flavors ($u,d,s$), SHARE with CHARM describes charm hadron production and decays. We observe, that according to present experimental results, charm decays mainly affect the yields of multistrange particles.