675 research outputs found
phi-meson in Nuclear Matter
-meson mass in nuclear matter () is investigated using an
effective Lagrangian of interacting with octet baryons.
decreases by a few \% in nuclear matter due to the current conservation and
effective nucleon/hyperon masses. Its implication to the p-A and A-A collisions
are briefly discussed.Comment: 7 pages, latex, 3 postscript figures, submitted to Prog. Theor. Phy
symmetry restoration in QCD with flavors
Recently, there have been reports that the chirally restored phase of QCD is
effectively symmetric under rather than . We supplement their argument by including the contributions from
topologically nontrivial gauge field configurations and discuss how the
conclusions are modified. General statements are made concerning the particle
spectrum of QCD with light flavors in the high temperature chirally
restored phase.Comment: 6 pages, no figures, revte
Color Superconductivity in Dense QCD and Structure of Cooper Pairs
The two-flavor color superconductivity is examined over a wide range of
baryon density with a single model. To study the structural change of Cooper
pairs, quark correlation in the color superconductor is calculated both in the
momentum space and in the coordinate space. At extremely high baryon density,
our model becomes equivalent to the usual perturbative QCD treatment and the
gap is shown to have a sharp peak near the Fermi surface due to the
weak-coupling nature of QCD. On the other hand, the gap is a smooth function of
the momentum at lower densities due to strong color magnetic and electric
interactions. The size of the Cooper pair is shown to become comparable to the
averaged inter-quark distance at low densities, which indicates a crossover
from BCS to BEC (Bose-Einstein condensation) of tightly bound Cooper pairs may
take place at low density.Comment: 6 pages, 5 figures. Invited talk at the Joint CSSM/JHF Workshop on
Physics at Japan Hadron Facility (March 14-21, Adelaide, 2002
Slavnov-Taylor identity for nonequilibrium quark-gluon plasma
Within the closed-time-path formalism of nonequilibrium QCD, we derive a
Slavnov-Taylor (ST) identity for the gluon polarization tensor. The ST identity
takes the same form both in Coulomb and covariant gauges. Application to
quasi-uniform quark-gluon plasma (QGP) near equilibrium or nonequilibrium
quasistationary QGP is made.Comment: 10page
Onset of Melting in Quark-Gluon Fluid at RHIC
A strong suppression in central Au+Au collisions has been observed
by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). We
develop a hydro+ model in which hot quark-gluon matter is described by
the full (3+1)-dimensional relativistic hydrodynamics and is treated
as an impurity traversing through the matter. The experimental
suppression pattern in mid-rapidity is reproduced well by the sequential
melting of , , and in dynamically expanding
fluid. The melting temperature of directly produced is well
constrained by the participant-number dependence of the suppression
and is found to be about with being the
pseudo-critical temperature.Comment: 5 pages, 5 figures, Submitted to Phys. Rev. C. (Rapid Communication
Transverse Quark Distribution in Mesons - QCD Sum Rule Approach -
QCD sum rules are used to compute the first few moments of the mesonic quark
momentum. Transverse, longitudinal and mixed transverse-longitudinal components
are examined. The transverse size of the pion is shown to be dictated by the
gluon condensate, even though the mass and the longitudinal distribution are
dominated by the quark condensate. The implications of our results for color
transparency physics and finite temperature QCD are discussed.Comment: 8 pages, Latex, Univ. of Washington preprint DOE/ER/40427-24-N9
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