Extreme States of Nuclear Matter: 1980

Abstract

Abstract. The theory of hot nuclear fireballs consisting of all possible finite-size hadronic constituents in chemical and thermal equilibrium is presented. As a complement of this hadronic gas phase characterized by maximal temperature and energy density, the quark bag description of the hadronic fireball is considered. Preliminary calculations of temperatures and mean transverse momenta of particles emitted in high multiplicity relativistic nuclear collisions together with some considerations on the observability of quark matter are offered. OverviewI wish to describe, as derived from known traits of strong interactions, the likely thermodynamic properties of hadronic matter in two different phases: the hadronic gas consisting of strongly interacting but individual baryons and mesons, and the dissolved phase of a relatively weakly interacting quark-gluon plasma. The equations of state of the hadronic gas can be used to derive the particle temperatures and mean transverse momenta in relativistic heavy ion collisons, while those of the quarkgluon plasma are more difficult to observe experimentally. They may lead to recognizable effects for strange particle yields. Clearly, the ultimate aim is to understand the behavior of hadronic matter in the region of the phase transition from gas to plasma and to find characteristic features which will allow its experimental observation. More work is still needed to reach this goal. This report is an account of my long and fruitful collaboration with R. Hagedorn [1].The theoretical techniques required for the description of the two phases are quite different: in the case of a The original address byline 1980 : Gesellschaft für Schwerionenforschung mbH, Darmstadt and Institut für Theoretische Physics der Universität Frankfurt/M; originally printed in GSI81-6 Orange Report, pp. 282-324, edited by R. Bock and R. Stock.b e-mail: rafelski@physics.arizona.edu hadronic gas, a strongly attractive interaction has to be accounted for, which leads to the formation of the numerous hadronic resonances -which are in fact bound states of several (anti) quarks. If this is really the case, then our intuition demands that at sufficiently high particle (baryon) density the individuality of such a bound state will be lost. In relativistic physics in particular, meson production at high temperatures might already lead to such a transition at moderate baryon density. As is currently believed, the quark-quark interaction is of moderate strength, allowing a perturbative treatment of the quark-gluon plasma as relativistic Fermi and Bose gases. As this is a very well studied technique to be found in several reviews [2][3][4][5][6][7][8], we shall present the relevant results for the relativistic Fermi gas and restrict the discussion to the interesting phenomenological consequences. Thus the theoretical part of this report will be devoted mainly to the strongly interacting phase of hadronic gas. We will also describe some experimental consequences for relativistic nuclear collisions such as particle t...

How We Got to QCD Matter from the Hadron Side: 1984

“…Thus, without having a formal proof, I believe one can justify asserting that SBM predicts a phase transition (of which not yet all details are known) to a quark- [119,120]. A further criticism was brought up by V.V.…”

Charm Jets

“…The mass of a strange-antistrange pair (2 * 95 MeV) is on a similar energy scale as the phase transition of hadronic matter into quark matter (QGP). Johann Rafelski and Rolf Hagedorn [26] proposed that the enhancement of strange quarks could be an observable signature of QGP, but it is important to note that strangeness enhancement can also occur in a thermalized hadronic system. Therefore, strangeness enhancement alone does not conclusively prove the formation of QGP.…”