Date of Award
Doctor of Philosophy
Physics and Astronomy
Craig A. Ogilvie
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.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Nathan Conrad Grau
Grau, Nathan Conrad, "Systematic study of high-pT di-jet correlations in nuclear collisions with the PHENIX experiment at RHIC " (2005). Retrospective Theses and Dissertations. 1733.