Brief history of the search for critical structures in heavy-ion collisions

Abstract

The paper briefly presents history, status, and plans of the search for the critical structures -the onset of fireball, the onset of deconfinement, and the deconfinement critical point -in high energy nucleus-nucleus collisions. First, the basic ideas are introduced, the history of the observation of strongly interacting matter in heavy ion collisions is reviewed, and the path towards the quark-gluon plasma discovery is sketched. Then the status of the search for critical structures is discussed -the discovery of the onset of deconfinement, indications for the onset of fireball, and still inconclusive results concerning the deconfinement critical point. Finally, an attempt to formulate priorities for future measurements -charm quarks vs the onset of deconfinement and detailed study of the onset of fireball -closes the paper.

Low mu and imaginary mu signals of a critical point in the phase diagram of an exactly soluble chiral symmetry breaking theory

“…Imaginary chemical potential solutions are found by simply allowing A t → iA t or d → id and repeating the process. The lagrangian with imaginary chemical potential is unchange except in the factor K in equation (18) where…”

“…This again might help distinguish boundaries of the regions with metastable vacua. See [18] for a recent summary of heavy ion collision searches for the QCD critical point.…”