Department of Physics
OSU Relativistic Heavy Ion Group
Research supported by the
National Science Foundation
At low excitation energy and near normal density, the properties of nuclear matter are fairly well understood. As nuclear systems become compressed or heated, a rich set of phenomena is observed, including multi-step particle production, in-medium modification of the particle properties, and at least one phase transition, from a liquid to a gaseous phase. At even higher energies and densities, a second phase transition is expected to occur, to the type of matter believed to have existed about one microsecond after the Big Bang. This transition, predicted by most models, involves the liberation of the quarks and gluons that make up the protons and neutrons inside the nucleus. The new state of matter, called the Quark Gluon Plasma, exists for only an instant, but study of its properties should challenge our understanding of the strong force in a regime where calculations are the most difficult.
To compress and heat nuclear matter, we study collisions of heavy nuclei (typically gold or lead) at the highest possible energies. This research involves collaborative experiments with very large particle detectors at national labs in the U.S. (BNL AGS: E895, E896, RHIC: STAR) and Europe (CERN SPS: NA44, LHC: ALICE). The OSU group is involved with detector (e.g. silicon drift) and software development and data analysis aimed at identifying and studying this second as-yet-unobserved phase transition in nuclear matter.