3,174 research outputs found
Critical Points in the Linear Sigma Model with Quarks
We employ a simple effective model to study the chiral dynamics of two
flavors of quarks at finite temperature and density. In particular, we
determine the phase diagram in the plane of temperature and baryon chemical
potential as a function of the pion mass. An interesting phase structure occurs
which results in zero, one or two critical points depending on the value of the
vacuum pion mass.Comment: 16 pages plus 5 figure
Modification of Z Boson Properties in Quark-Gluon Plasma
We calculate the change in the effective mass and width of a Z boson in the
environment of a quark-gluon plasma under the conditions expected in Pb-Pb
collisions at the LHC. The change in width is predicted to be only about 1 MeV
at a temperature of 1 GeV, compared to the natural width of 24907 MeV. The
mass shift is even smaller. Hence no observable effects are to be expected.Comment: 7 pages latex file with 6 embedded PS figure
Two-Loop Self-Energy and Multiple Scattering at Finite Temperature
One and two loop self-energies are worked out explicitly for a heavy scalar
field interacting weakly with a light self-interacting scalar field at finite
temperature. The ring/daisy diagrams and a set of necklace diagrams can be
summed simultaneously. This simple model serves to illustrate the connection
between multi-loop self-energy diagrams and multiple scattering in a medium.Comment: 15 pages including 7 figures; v2. with appendix added, accepted by
PR
Hydrogen-like Atoms from Ultrarelativistic Nuclear Collisions
The number of hydrogen-like atoms produced when heavy nuclei collide is
estimated for central collisions at the Relativistic Heavy Ion Collider using
the sudden approximation of Baym et al. As first suggested by Schwartz, a
simultaneous measurement of the hydrogen and hadron spectra will allow an
inference of the electron or muon spectra at low momentum where a direct
experimental measurement is not feasible.Comment: 6 pages, 4 figure
Background field method at finite temperature and density
In this letter we make use of the Background Field Method (BFM) to compute
the effective potential of an SU(2) gauge field theory, in the presence of
chemical potential and temperature. The main idea is to consider the chemical
potential as the background field. The gauge fixing condition required by the
BFM turns out to be exactly the one we found in a previous article in a
different context.Comment: 6 pages, no figure
Strange Fluctuations at RHIC
Robust statistical observables can be used to extract the novel isospin
fluctuations from background contributions in K-short K-plus measurements in
nuclear collisions. To illustrate how this can be done, we present new HIJING
and UrQMD computations of these observables.Comment: 4 pages, 2 figures, talk at Quark Matter 200
Basic Treatment of QCD Phase Transition Bubble Nucleation
Starting from the QCD Lagrangian and the surface tension of QCD bubbles we
derive the critical size of bubbles, the nucleation probability and the
nucleation site separation distance. We find the separation of sites is more
than an order of magnitude larger than previous QCD model estimates, which
could lead to observable effects.Comment: 8 pages, one figur
Inhomogeneous Nucleation of Quark-Gluon Plasma in High Energy Nuclear Collisions
We estimate the probability that a hard nucleon-nucleon collision is able to
nucleate a seed of quark--gluon plasma in the surrounding hot and dense
hadronic matter formed during a central collision of two large nuclei at AGS
energies. The probability of producing at least one such seed is on the order
of 1-100\%. We investigate the influence of quark--gluon plasma formation on
the observed multiplicity distribution and find that it may lead to noticable
structure in the form of a bump or shoulder.Comment: 16 pages, latex and 12 ps figures available on reques
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