Multi-Quark Hadrons and S=-2 Hypernuclei

The general character of 4-quark (mesonic) and strange 6-quark (baryonic) quark systems is very briefly reviewed a la Jaffe, i.e. in the MIT bag, and so far still possibly viable candidates are indicated. Concentration is on S=-2 systems. Traditionally, one employs the (K^-,K^+) reaction on a relatively light target and hopes to retain two units of strangeness on a single final state fragment. Alternatively, heavy ion reactions can be used to produce Lambda-hyperons copiously and one seeks to observe coalescence of two of these particles into the lightest S=-2 nucleus, the H-dibaryon. The complications arising from the presence of a repulsive core in the baryon-baryon interaction on the production of the H are discussed. Also considered is the possible presence in the data from the AGS experiment E906, of slightly heavier S=-2 nuclei, in particular_{Lambda Lambda}^{4}H

Elliptical Flow in Relativistic Ion Collisions at s^(1/2)= 200 A GeV

A consistent picture of the Au+Au and D+Au, s^1/2 = 200 A GeV measurements at RHIC obtained with the PHENIX, STAR, PHOBOS and BRAHMS detectors including both the rapidity and transverse momentum spectra was previously developed with the simulation LUCIFER. The approach was modeled on the early production of a fluid of pre-hadrons after the completion of an initial, phase of high energy interactions. The formation of pre-hadrons is discussed here, in a perturbative QCD approach as advocated by Kopeliovich, Nemchik and Schmidt. In the second phase of LUCIFER, a considerably lower energy hadron-like cascade ensues. Since the dominant collisions occurring in this latter phase are meson-meson in character while the initial collisions are between baryons, i.e. both involve hadron sized interaction cross-sections, there is good reason to suspect that the observed elliptical flow will be produced naturally, and this is indeed found to be the case.Comment: 7 pages, 6 figure

Pbar Annihilation in Au+Au at AGS Energies

Antinucleon production in heavy ion collisions is potentially an excellent signal for unusual phenomena in hot and dense matter. However, at the low energies available at the AGS the annihilation process must be handled with care. In this Comment, we consider the case of Au + Au collisions at approximately 11 GeV/c, applying the ARC treatment of pbar production and annihilation to the analysis of experiment E878. It is apparent that classical screening introduced for Si + Au is crucial in the understanding of data obtained with the more massive projectile. Unfortunately, there seems no necessity for invoking unusual behaviour in the Au + Au system.Comment: 1 page in revtex, 1 postscript fil