The Quark-Gluon Plasma Comes of Age

Peter Jacobs

LBNL

Abstract: "Quantum Chromodynamics (QCD) is without doubt the correct theory of the strong interaction. QCD matter is expected to have an interesting and complex phase structure, including a deconfined and chirally-restored phase at high temperature (the Quark-Gluon Plasma), but QCD calculations are in general difficult due to the self-interaction of the gluon. Good theoretical progress in understanding the phase diagram has nevertheless been made, primarily through numerical simulations on the lattice. Experimental progress using ultra-relativistic nuclear collisions has proved more difficult to achieve, despite a huge international effort over many years and some misleading (or at least confusing) QGP discovery announcements. The experimental situation is now changing, however, thanks to dramatic experimental effects discovered at RHIC and to theoretical progress in interpreting them quantitatively. I will discuss these developments, what I think we are learning about highly excited strongly interacting matter, and the future prospects at RHIC and the LHC. Finally, it was conjectured recently that a deep connection exists between non-abelian gauge theories and quantum gravity. Time permitting, I will discuss what little I know about this provocative development in string theory and its potential consequences for heavy ion collisions."