Production of strange clusters by Quark-Gluon-Plasma fragmentation

Abstract

Abstract.We discuss the production of strange quark clusters in high energy heavy ion reactions in which a Quark-Gluon-Plasma (QGP) intermediate state is excited. A microscopic fission-chain model (PHASER) has been constructed for the description of QGP rehadronization. Color fluctuations, Q(2 pair production and energy fragmentation have been taken into account. We determined the spin-flavor degeneracy factors and the formation factors for multibaryon quark clusters. Baryon, antibaryon and meson yields have been estimated, as well as those of light multi-strange quark clusters. 12.38.Mk; 25.75. +r PACS: 1.IntroductionThe production and identification of the Quark-GluonPlasma (QGP) state represents a central problem in contemporary nuclear physics. At high enough energy and baryon number, relativistic heavy ion collisions can provide sufficiently high temperature and density for quark and gluon liberation, i.e. the deconfinement phase transition. Heavy ion reactions which pass through the QGP intermediate state are expected to be a powerful tool to produce exotic hadrons and hadronic clusters. Experiments are in progress at the Brookhaven AGS at 14.5 GeV/A and at the CERN SPS at 200 GeV/A beam energies to synthesize and detect the QGP phase. Future experiments at higher energies are planned at the RHIC facility at Brookhaven and the LHC at CERN. The formation of stable multistrange quark clusters ("strangelets"), if such objects indeed exist, could offer a signature of QGP formation. This manuscript has been authored under contract number DE-AC02-76CH00016 with the U.S. Department of Energy. Accordingly, the U.S. Government retains a non-exclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes We have formulated a plasma fragmentation mechanism for QGP hadronization. This mechanism provides a new way (besides strangeness separation in the quarkhadron coexistence phase during hadronization) to produce exotic strange clusters. There are theoretical suggestions that strange quark clusters could be stable against strong decay. In addition, antinuclei and anti-strange clusters might be produced in measurable amounts in relativistic heavy ion collisions, if QGP formation occurs.In Sect. 2, we describe in detail our fission-chain model (PHASER) for the description of the hadronization phase transition. In Sect. 3, we discuss the parameters of the initial QGP state. In Sect. 4, baryon and antibaryon yields in the final hadron gas are calculated and the entropy conservation law is discussed. The p/~t, K/~ and some antibaryon/baryon ratios are also presented. Section 5 is devoted to a discussion of the results for light strange cluster yields and ratios. We discuss our predictions in a qualitative way and point out some limitations of our approach. The fission-chain model of QGP fragmentationAfter the QGP state is produced, a crucial question is the mechanism for the rehadronization of QGP. A careful treatment of rehadronizat...

The physics programme of the MoEDAL experiment at the LHC

“…Coalescence models [347,348] provide another production mechanism for strangelets, whereby hypernuclei produced in heavy-ion interactions could decay to strangelets. However, it should be pointed out that the good agreement of measurements of particle production at RHIC with simple thermodynamic models severely constrains the production of strangelets in heavy-ion collisions at the LHC [349].…”

Entropy Production and Particle Yields in Heavy Ion Collisions at LHC

“…This decision will be done in the next Section; now let us see the models used here. Calculations in models 1-10 were made a few times; of course, in contexts of much lower energies [9,10,11,12,13]. We consider here 10 rehadronisation models (+1 without QGP) from amongst the virtual infinity of them.…”

“…The 3 numbers are regarded digital, and then add 1: so they are indeed Models 1-8. Model 9 is the absence of QGP phase at all, for simplicity's sake with complete thermal, chemical and mechanical equilibrium throughout the whole collision, and Model 10 is a sequential fission one [11]. A comparison of the results of Models 1-10 was given in [15] up to SPS energies.…”

“…A group of physicists in Budapest recognised in 1987 that calculations of heavy ion collision events need i) thermodynamic approach because of the lack of any a priori knowledge about rehadronisation processes; and ii) the development of a self-consistent anisotropic continuum dynamics proper for numeric calculations, because of transparency in ultrarelativistic collisions [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17].…”