Degree Type

Dissertation

Date of Award

2005

Degree Name

Doctor of Philosophy

Department

Physics and Astronomy

First Advisor

Craig A. Ogilvie

Abstract

One major goal of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory on Long Island, New York, is to create and study the quark-gluon plasma (QGP). This state of matter results from the phase transition of Quantum Chromodynamics (QCD) at extremely high temperature (1012 K) and densities (100 times normal nuclear matter). Au ions are collided in an attempt to increase the temperature necessary to cross the phase boundary. To study the properties of this new matter, high energy jets are used as a probe. Jets are a collimated spray of hadrons resulting from the fragmentation of high-energy quarks and gluons (partons). Observations from single particles with large momentum transverse to the beam direction (PT) suggest that jets are suppressed or quenched due to energy loss from to strong interactions with the medium;This thesis presents, for the first time, a systematic study of jets from nuclear collisions. These jet measurements further constrain models of energy loss which reproduce the measured suppression in Au+Au collisions. A detailed study of jet properties using two-particle azimuthal correlations, a statistical method to detect jets, is performed. It is found that d+Au jet properties are very similar to those in p+p collisions. This indicates that the cold nuclear medium does not strongly modify jets at RHIC energies. In Au+Au collisions a suppression of jet yields is observed but not to the level of the single particle suppression. A consequence of energy loss models is a large broadening of the di-jet distribution. Little to no broadening is observed. At the present time there is no consistent picture of energy loss based on the available data from single particle spectra and from di-jet correlations.

DOI

https://doi.org/10.31274/rtd-180813-15376

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Nathan Conrad Grau

Language

en

Proquest ID

AAI3200420

File Format

application/pdf

File Size

206 pages

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