1,075 research outputs found
A Phenomenological Treatment of Chiral Symmetry Restoration and Deconfinement
A phenomenological expression for the thermodynamic potential of gluons and
quarks is constructed which incorporates the features of deconfinement and
chiral symmetry restoration known from lattice simulations. The thermodynamic
potential is a function of the Polyakov loop and chiral condensate expectation
values. The gluonic sector uses a successful model for pure (SU(N_c)) gauge
theories in which the Polyakov loop eigenvalues are the fundamental order
parameters for deconfinement. The quark sector is given by a Nambu-Jona-Lasinio
model in which a constant background (A_0) field couples the chiral condensate
to the Polyakov loop. We consider the case of (N_f = 2) in detail. For two
massless quarks, we find a second order chiral phase transition. Confinement
effects push the transition to higher temperatures, but the entropy associated
with the gluonic sector acts in the opposite direction. For light mass quarks,
only a rapid crossover occurs. For sufficiently heavy quarks, a first order
deconfinement transition emerges. This simplest model has one adjustable
parameter, which can be set from the chiral transition temperature for light
quarks. It predicts all thermodynamic quantities as well as the behavior of the
chiral condensate and the Polyakov loop over a wide range of temperatures.Comment: 3 pages, 4 eps figures, Lattice 2002 conference contribution,
Lattice2002(nonzerot
Wilson Polynomials and the Lorentz Transformation Properties of the Parity Operator
The parity operator for a parity-symmetric quantum field theory transforms as
an infinite sum of irreducible representations of the homogeneous Lorentz
group. These representations are connected with Wilson polynomials
Flavor Relationships Among Muscles of the Beef Chuck and Round
Flavor relationships among muscles and causes of liver-like off-flavor of six muscles from each of 30 beef carcasses were evaluated by a trained sensory panel. The infraspinatus (flat iron) was lowest in sour, metallic, and oxidized flavors and highest in fatty flavor. The vastus lateralis (knuckle side) had the most intense off-flavor and was among the highest for sour and oxidized. Heme iron concentration and pH were lowly related to off-flavor. Of 18 muscles from three carcasses, 16 were high in liver-like off-flavor. These data suggest liver-like off-flavor is related to something that impacts the entire animal
Complete High Temperature Expansions for One-Loop Finite Temperature Effects
We develop exact, simple closed form expressions for partition functions
associated with relativistic bosons and fermions in odd spatial dimensions.
These expressions, valid at high temperature, include the effects of a
non-trivial Polyakov loop and generalize well-known high temperature
expansions. The key technical point is the proof of a set of Bessel function
identities which resum low temperature expansions into high temperature
expansions. The complete expressions for these partition functions can be used
to obtain one-loop finite temperature contributions to effective potentials,
and thus free energies and pressures.Comment: 9 pages, RevTeX, no figures. To be published in Phys. Rev D. v2 has
revised introduction and conclusions, plus a few typographical errors are
corrected; v3 corrects one typ
Flavor Relationships Among Muscles of the Beef Chuck and Round
Flavor relationships among muscles and causes of liver-like off-flavor of six muscles from each of 30 beef carcasses were evaluated by a trained sensory panel. The infraspinatus (flat iron) was lowest in sour, metallic, and oxidized flavors and highest in fatty flavor. The vastus lateralis (knuckle side) had the most intense off-flavor and was among the highest for sour and oxidized. Heme iron concentration and pH were lowly related to off-flavor. Of 18 muscles from three carcasses, 16 were high in liver-like off-flavor. These data suggest liver-like off-flavor is related to something that impacts the entire animal
The Finite Temperature SU(2) Savvidy Model with a Non-trivial Polyakov Loop
We calculate the complete one-loop effective potential for SU(2) gauge bosons
at temperature T as a function of two variables: phi, the angle associated with
a non-trivial Polyakov loop, and H, a constant background chromomagnetic field.
Using techniques broadly applicable to finite temperature field theories, we
develop both low and high temperature expansions. At low temperatures, the real
part of the effective potential V_R indicates a rich phase structure, with a
discontinuous alternation between confined (phi=pi) and deconfined phases
(phi=0). The background field H moves slowly upward from its zero-temperature
value as T increases, in such a way that sqrt(gH)/(pi T) is approximately an
integer. Beyond a certain temperature on the order of sqrt(gH), the deconfined
phase is always preferred. At high temperatures, where asymptotic freedom
applies, the deconfined phase phi=0 is always preferred, and sqrt(gH) is of
order g^2(T)T. The imaginary part of the effective potential is non-zero at the
global minimum of V_R for all temperatures. A non-perturbative magnetic
screening mass of the form M_m = cg^2(T)T with a sufficiently large coefficient
c removes this instability at high temperature, leading to a stable
high-temperature phase with phi=0 and H=0, characteristic of a
weakly-interacting gas of gauge particles. The value of M_m obtained is
comparable with lattice estimates.Comment: 28 pages, 5 eps figures; RevTeX 3 with graphic
Gluon Quasiparticles and the Polyakov Loop
A synthesis of Polyakov loop models of the deconfinement transition and
quasiparticle models of gluon plasma thermodynamics leads to a class of models
in which gluon quasiparticles move in a non-trivial Polyakov loop background.
These models are successful candidates for explaining both critical behavior
and the equation of state for the SU(3) gauge theory at temperatures above the
deconfinement temperature T_c. Polyakov loops effects are most important at
intermediate temperatures from T_c up to roughly 2.5 T_c, while quasiparticle
mass effects provide the dominant correction to blackbody behavior at higher
temperatures.Comment: 6 pages, 7 eps figures, revtex
Flavor Relationships among Muscles form the Beef Chuck and Round
This research compared off-flavor notes and the relationship of pH and heme-iron content to off-flavor for different beef muscles. After grading, knuckles and shoulder clods were removed from 16 USDA Choice and 14 USDA Select beef carcasses, vacuum- packaged, and aged for 7 d. The rectus femoris (REC), vastus medalis (VAM), vastus lateralis (VAL), teres major (TER), infraspinatus (INF), and triceps brachii-long head (TRI) were separated, cut into steaks, and frozen (â16°C). Sensory analysis was conducted using a trained taste panel, with steaks grilled to an internal temperature of 65°C. Heme-iron concentration and pH were determined. The INF had lower (P \u3c 0.05) off-flavor intensity ratings and less frequent sour flavor than the other muscles, and the VAL had the most intense (P \u3c 0.05) off-flavor ratings and among the greatest frequency of sour, charred, and oxidized flavors. The frequencies of liver-like, bloody, and rancid flavors were not affected by muscle type. Heme-iron concentration did not differ among muscles. Three USDA Select carcasses had intense off-flavor in the muscles. Liver-like flavor was highly negatively correlated with off-flavor intensity for each of the muscles tested. Muscles rated a 5 or below (on an 8-point rating scale, where 1 = extremely intense off-flavor and 8 = no off-flavor) in off-flavor intensity and identified as liver-like by 30% or more of the panelists were grouped together and compared to normal muscles. Those in the liver-flavored group were less frequently identified as charred, probably because the liver-like flavor was so intense. There were no differences between the 2 groups for sour, metallic, bloody, oxidized, or fatty off-flavor notes. Regression equations containing the linear and quadratic functions of heme-iron concentration, muscle pH, and their interaction were established for the frequency of off-flavor notes within each muscle. The REC, TER, VAL, and VAM showed a relationship between pH, heme iron, and off-flavor intensity (P \u3c 0.05). Liver-like flavor was explained partially by pH and heme iron in the REC, VAM, and VAL (R2 = 0.45 to 0.55; P \u3c 0.05). Few other significant relationships were found. Heme iron and pH were unrelated to metallic, oxidized, or rancid flavors for any of the muscles tested. These data suggest that liver-like off-flavors are specific to individual animals, and that pH and heme iron are not strongly related to off-flavor notes
Phenomenological Equations of State for the Quark-Gluon Plasma
Two phenomenological models describing an SU(N) quark-gluon plasma are
presented. The first is obtained from high temperature expansions of the free
energy of a massive gluon, while the second is derived by demanding color
neutrality over a certain length scale. Each model has a single free parameter,
exhibits behavior similar to lattice simulations over the range T_d - 5T_d, and
has the correct blackbody behavior for large temperatures. The N = 2
deconfinement transition is second order in both models, while N = 3,4, and 5
are first order. Both models appear to have a smooth large-N limit. For N >= 4,
it is shown that the trace of the Polyakov loop is insufficient to characterize
the phase structure; the free energy is best described using the eigenvalues of
the Polyakov loop. In both models, the confined phase is characterized by a
mutual repulsion of Polyakov loop eigenvalues that makes the Polyakov loop
expectation value zero. In the deconfined phase, the rotation of the
eigenvalues in the complex plane towards 1 is responsible for the approach to
the blackbody limit over the range T_d - 5T_d. The addition of massless quarks
in SU(3) breaks Z(3) symmetry weakly and eliminates the deconfining phase
transition. In contrast, a first-order phase transition persists with
sufficiently heavy quarks.Comment: 22 pages, RevTeX, 9 eps file
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