42 research outputs found
Properties of Dense Strange Hadronic Matter with Quark Degrees of Freedom
The properties of strange hadronic matter are studied in the context of the
modified quark-meson coupling model using two substantially different sets of
hyperon-hyperon () interactions. The first set is based on the Nijmegen
hard core potential model D with slightly attractive interactions. The
second potential set is based on the recent SU(3) extension of the Nijmegen
soft-core potential NSC97 with strongly attractive interactions which may
allow for deeply bound hypernuclear matter. The results show that, for the
first potential set, the hyperon does not appear at all in the bulk at
any baryon density and for all strangeness fractions. The binding energy curves
of the resulting system vary smoothly with density and the system
is stable (or metastable if we include the weak force). However, the situation
is drastically changed when using the second set where the hyperons
appear in the system at large baryon densities above a critical strangeness
fraction. We find strange hadronic matter undergoes a first order phase
transition from a system to a for strangeness
fractions and baryonic densities exceeding twice ordinary nuclear
matter density. Furthermore, it is found that the system built of
is deeply bound. This phase transition affects significantly the equation of
state which becomes much softer and a substantial drop in energy density and
pressure are detected as the phase transition takes place.Comment: 25 pages latex and 12 figures in postscript forma
Properties of dense strange hadronic matter with quark degrees of freedom
The properties of strange hadronic matter are studied in the context of the modified quark-meson coupling model using two substantially di erent sets of hyperon-hyperon (Y Y ) interactions. The first set is based on the Nijmegen hard core potential model D with slightly attractive Y Y interactions. The second potential set is based on the recent SU(3) extension of the Nijmegen soft-core potential NSC97 with strongly attractive Y Y interactions which may allow for deeply bound hypernuclear matter. The results show that, for the first potential set, the hyperon does not appear at all in the bulk at any baryon density and for all strangeness fractions. The binding energy curves of the resulting N system vary smoothly with density and the system is stable (or metastable if we include the weak force). However, the situation is drastically changed when using the second set where the hyperons appear in the system at large baryon densities above a critical strangeness fraction. We find strange hadronic matter undergoes a first order phase transition from a N system to a N for strangeness fractions fS > 1.2 and baryonic densities exceeding twice ordinary nuclear matter density. Furthermore, it is found that the system built of N is deeply bound. This phase transition a ects significantly the equation of state which becomes much softer and a substantial drop in energy density and pressure are detected as the phase transition takes place. PACS:21.65.+f, 24.85.+p, 12.39B
Hot nuclear matter in the modified quark-meson coupling model with quark-quark correlations
Short-range quark-quark correlations in hot nuclear matter are examined
within the modified quark-meson coupling model (MQMC) by adding repulsive
scalar and vector quark-quark interactions. Without these correlations, the bag
radius increases with the baryon density. However when the correlations are
introduced the bag size shrinks as the bags overlap. Also as the strength of
the scalar quark-quark correlation is increased, the decrease of the effective
nucleon mass with the baryonic density is slowed down and tends to
saturate at high densities. Within this model we study the phase transition
from the baryon-meson phase to the quark-gluon plasma (QGP) phase with the
latter modeled as an ideal gas of quarks and gluons inside a bag. Two models
for the QGP bag parameter are considered. In one case, the bag is taken to be
medium-independent and the phase transition from the hadron phase to QGP is
found to occur at 5-8 times ordinary nuclear matter density for temperatures
less than 60 MeV. For lower densities, the transition takes place at higher
temperature reaching up to 130 MeV at zero density. In the second case, the QGP
bag parameter is considered medium-dependent as in the MQMC model for the
hadronic phase. In this case, it is found that the phase transition occurs at
much lower densities.Comment: 8 pages, latex, 4 eps figure
The thermodynamics for a hadronic gas of fireballs with internal color structures and chiral fields
The thermodynamical partition function for a gas of color-singlet bags
consisting of fundamental and adjoint particles in both and
group representations is reviewed in detail. The constituent particle species
are assumed to satisfy various thermodynamical statistics. The gas of bags is
probed to study the phase transition for a nuclear matter in the extreme
conditions. These bags are interpreted as the Hagedorn states and they are the
highly excited hadronic states which are produced below the phase transition
point to the quark-gluon plasma. The hadronic density of states has the
Gross-Witten critical point and exhibits a third order phase transition from a
hadronic phase dominated by the discrete low-lying hadronic mass spectrum
particles to another hadronic phase dominated by the continuous Hagedorn
states. The Hagedorn threshold production is found just above the highest known
experimental discrete low-lying hadronic mass spectrum. The subsequent Hagedorn
phase undergoes a first order deconfinement phase transition to an explosive
quark-gluon plasma. The role of the chiral phase transition in the phases of
the discrete low-lying mass spectrum and the continuous Hagedorn mass spectrum
is also considered. It is found crucial in the phase transition diagram.
Alternate scenarios are briefly discussed for the Hagedorn gas undergoes a
higher order phase transition through multi-processes of internal color-flavor
structure modification.Comment: 110 pages and 13 figures. Added references to the introductio
Hot hypernuclear matter in the modified quark meson coupling model
Hot hypernuclear matter is investigated in an explicit SU(3) quark model based on a mean field description of nonoverlapping baryon bags bound by the self-consistent exchange of scalar sigma, zeta and vector omega,phi mesons. The sigma, omega mean fields are assumed to couple to the u, d-quarks while the zeta ,phi mean fields are coupled to the s-quark. The coupling constants of the mean fields with the quarks are assumed to satisfy SU(6) symmetry. The calculations take into account the medium dependence of the bag parameter on the scalar fields sigma, zeta. We consider only the octet baryons N,Lambda,Sigma, Xi in hypernuclear matter. An ideal gas of the strange mesons K and K is introduced to keep zero net strangeness density. Our results for symmetric hypernuclear matter show that a phase transition takes place at a critical temperature around 180 MeV in which the scalar mean fields sigma, zeta take nonzero values at zero baryon density. Furthermore, the bag contants of the baryons decrease significantly at and above this critical temperature indicating the onset of quark deconfinement. The present results imply that the onset of quark deconfinement in SU(3) hypernuclear matter is much stronger than in SU(2) nuclear matter. PACS:21.65.+f, 24.85.+p, 12.39B
Reversible myocardial calcification following severe leptospirosis complicated with rhabdomyolysis-induced acute kidney injury and magnesium-wasting nephropathy
We present a patient with leptospirosis infection who presented septic
shock with multiple-organ dysfunction syndrome, severe rhabdomyolysis
and acute myocarditis. He developed biphasic blood
calcium pattern with hypocalcemia in the oliguric phase followed
by hypercalcemia during the recovery diuretic phase in the context
of rhabdomyolysis and oliguric acute kidney injury. Meanwhile,
he developed an extensive calcification of the myocardium. Severe
renal magnesium wasting was observed during the convalescence
phase. Follow-up showed progressive resorption and later almost
total disappearance of the calcific deposits in the heart by the 18th
month after discharge. Renal magnesium wasting decreased gradually,
but yet persisted beyond the 18th and was normalized only by
the 36th month after discharge. We discuss the pathophysiologic
mechanisms involved in the myocardial calcification and renal
magnesium wasting and suggest a possibility of a contributing role
of magnesium renal wasting in mobilization of calcium deposits out of myocardiu
Adrenal Insufficiency in Metastatic Lung Cancer
We report a case of adrenal insufficiency in patient with lung cancer. Although adrenal metastases are common in cancer patients, adrenal insufficiency is a rare occurrence. Diagnosis and treatment of adrenal insufficiency will improve the physical status and the quality of life in those patients
Numerical solution of the color superconductivity gap in a weak coupling constant
We present the numerical solution of the full gap equation in a weak coupling
constant . It is found that the standard approximations to derive the gap
equation to the leading order of coupling constant are essential for a secure
numerical evaluation of the logarithmic singularity with a small coupling
constant. The approximate integral gap equation with a very small should be
inverted to a soft integral equation to smooth the logarithmic singularity near
the Fermi surface. The full gap equation is solved for a rather large coupling
constant . The approximate and soft integral gap equations are solved
for small values. When their solutions are extrapolated to larger
values, they coincide the full gap equation solution near the Fermi surface.
Furthermore, the analytical solution matches the numerical one up to the order
one O(1). Our results confirm the previous estimates that the gap energy is of
the order tens to 100 MeV for the chemical potential MeV. They
also support the validity of leading approximations applied to the full gap
equation to derive the soft integral gap equation and its analytical solution
near the Fermi surface.Comment: 7 pages+ 6 figs, Stanford, Frankfurt and Bethlehe
Hot Nuclear Matter in the Quark Meson Coupling Model with Dilatons
We study hot nuclear matter in an explicit quark model based on a mean field
description of nonoverlapping nucleon bags bound by the self-consistent
exchange of scalar and vector mesons as well as the glueball field. The
glueball exchange as well as a realization of the broken scale invariance of
quantum chromodynamics is achieved through the introduction of a dilaton field.
The calculations also take into account the medium-dependence of the bag
constant. The effective potential with dilatons is applied to nuclear matter.
The nucleon properties at finite temperature as calculated here are found to be
appreciably different from cold nuclear matter. The introduction of the dilaton
potential improves the shape of the saturation curve at T=0 and is found to
affect hot nuclear matter significantly.Comment: LaTeX/TeX 12 pages (zak2), 13 figures in TeX forma