502 research outputs found
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
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