The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory is in the middle of its first long production run for physics. In collisions of heavy nuclei at RHIC, nuclear matter is compressed and heated to energy densities expected only in the cores of dense stars and within the first microseconds after the Big Bang. At such large energy densities nuclear matter is predicted to "melt" and form a plasma of deconfined quarks and gluons. The long-term goals of experiments at RHIC and of future heavy ion experiments at the Large Hadron Collider are to create and study hot dense matter, to uniquely identify the quark-gluon plasma, and to study its properties.

The STAR experiment at RHIC consists of detectors for charged particle tracking and particle identification over a large solid angle. Initial measurements include identified particle spectra to large momenta, particle correlations and flow, and production of anti-particles and light anti-nuclei. This information has been used to help understand the degree of chemical and thermal equilibration; the dynamical evolution of these collisions in the early, expansion, and late stages; and parton propagation through the medium. After a brief introduction to the field, the STAR experiment and physics results will be presented. I will make comparisons with experimental results in other systems and at other energies, in order to better understand and emphasize the implications and to address the question in the title.

ANL Physics Division Colloquium Schedule