Characterization of the Transition Region in the QCD Phase Diagram

The study of the Quantum Chromodynamics (QCD) phase diagram has been the object of great effort in the scientific community both from theory and experiment, and has been investigated from first principles through lattice simulations in the low density regime. The transition between ordinary matter and a deconfined Quark Gluon Plasma was shown from lattice QCD to be a smooth crossover. It is probed experimentally in relativistic heavy-ion collisions at the Brookhaven National Laboratiory (BNL) and CERN, where sufficiently high temperatures are reached to create such a system. This transition is believed to become of the first order at large baryon density, implying the existence of a critical point. The search for such a point is the main goal of the second Beam Energy Scan (BES-II) program at BNL. In this dissertation, I focus on the transition region of the QCD phase diagram by calculating several observables with different theoretical approaches. In the first part of this work, I study the moment in heavy-ion collisions at which the chemical composition of the system is fixed: the chemical freeze-out. I compare net-particle fluctuations calculated in the Hadron Resonance Gas (HRG) model to experimental data to determine the chemical freeze-out temperature, with particular attention on the dependence of such temperature on the flavor composition of the particles. A separate analysis is performed to study the content of the hadron spectrum, through a comparison of HRG model and lattice QCD results. I also generate a family of Equations of State (EoS) for QCD matching lattice calculations at low baryon density, and including a critical point in the correct universality class. Moreover, I investigate the consequences of the critical point on measurable quantities, providing guidance for the forthcoming data from the BES. Finally, in light of the recent extension of hydrodynamic simulations to include all conserved charges of strong interactions, I produce an EoS for QCD that depends on all three chemical potentials. I then study the impact of these additional conserved charges on the thermodynamics when realistic conditions on the composition of the system are imposed.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Physics

Grantor

University of Houston

Year dc:date.issued

2019

Author dc:creator

• Parotto, Paolo 1989-

Advisor dc:contributor.advisor

• Ratti, Claudia

Committee members dc:contributor.committeemember

• Gunaratne, Gemunu H.
• Labate, Demetrio
• Timmins, Anthony
• Koerner, Lisa W.

• Quark-gluon plasma
• Heavy-Ion Collisions
• Equation of State

Statement dc:rights

• The author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. UH Libraries has secured permission to reproduce any and all previously published materials contained in the work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/10657/5785

OAI identifier oai:identifier

oai:uh-ir.tdl.org:10657/5785