This workshop will consist of invited speakers and general participants to whom we unfortunately cannot offer a support for local expenses to stay in Trento. If you have not received an invitation and would like to attend the workshop, please contact the organizers to ask for vacancies.

Main Topics

Topics to be discussed include:
  1. Experimental situation and systematics in the T-μ plane.
  2. Implications of large Nc for the QCD phase diagram.
  3. Beyond large Nc.
  4. Solvable models with confinement and chiral symmetry.
  5. Implications for heavy ion collision programs and astrophysics.

Aim

A purpose of this workshop is to gather theorists -- QCD phenomenologists, lattice practitioners, and string theorists -- as well as experimentalists, to attack problems related to confinement, chiral symmetry, and their interrelations in cold, dense matter in QCD. Understanding these issues would have a direct impact on proper formulation of planned experimental programs to explore the QCD phase diagram at large baryon density at BNL, GSI and JINR, as well as our understanding of different astrophysical phenomena in neutron stars and the like.

For the last three decades, it was believed that upon increasing temperature and density, that the phase transitions for deconfinement and chiral symmetry breaking coincide, forming an approximate semicircle in the plane of temperature T, and (quark or baryon) chemical potential μ. At small densities and high temperature, we know from numerical simulations on the lattice that, indeed, both transitions do appear to coincide, or are close to one another, in a cross-over regime of T=150--200MeV. At large baryon densities an ab initio solution of QCD on the lattice is not possible, and the only source of information is from models. From the 't Hooft anomaly matching conditions, we know that in vacuum, confinement necessarily implies chiral symmetry breaking. The very interesting question is whether or not this persists in a medium.

Recently it has been argued that the two transitions do not coincide in the limit of a large number of colors, Nc. For cold, dense quark matter, there is what has been termed "Quarkyonic Matter", which is confined. At some critical density chiral symmetry might be restored in such a phase, and consequently there could appear a phase which is confined, but chirally symmetric. The generation of mass within such a phase should be very different from that in vacuum.

It is not clear at the moment what this phase would look like: is it a Fermi liquid, or does confinement produce non-Fermi liquid behavior? For large Nc, it might be a crystal, but are there chiral density waves? The transport properties within such a phase should be determined by properties of hadronic excitations near the Fermi surface. An importan issue is to match properties of Quarkyonic Matter with some known properties of the nuclear matter at moderate densities.

If such a phase does exist, then where is it located on the QCD phase diagram? What is the order of phase transition for chiral symmetry? Is there a critical end-point? All of these questions are of key importance for future experimental programs and for our proper understanding of QCD.



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