15079524
NON-ABELIAN MEDIUM EFFECTS IN QUARK–GLUON PLASMA
Based on the kinetic theory, the non-Abelian medium property of hot Quark–Gluon Plasma is investigated. The nonlinearity of the plasma comes from two aspects: The nonlinear wave–wave interaction and self-interaction of color field. The non-Abelian color permittivity is obtained by expanding the kinetic equations to third order. As an application, the nonlinear Landau damping rate and the nonlinear eigen frequency shift are calculated in the longwave length limit.
124840820
Finite-temperature nuclear matter properties within a relativistic σ − ω coupling model
We use the relativistic mean field theory to study the finite temperature nuclear matter properties. The effects of isoscalar $\ensuremath{\sigma}\text{\ensuremath{-}}\ensuremath{\omega}$ coupling on the equation of state and finite temperature properties of symmetric and asymmetric nuclear matter are investigated carefully. For comparison, we also discuss the properties of two nonlinear $\ensuremath{\sigma}$ self-coupling models, namely NL-SH and NL3. It is found that the $\ensuremath{\sigma}\text{\ensuremath{-}}\ensuremath{\omega}$ coupling term can soften the equation of state, but has very limited influence to the critical temperature of the nuclear matter liquid-gas phase transition.
124341359
Thomson Problem approach to relativistic Dirac fermions ground state energy in the unitary limit
125706576
Novel effects of electromagnetic interaction on the correlation of nuclear matter
122544309
THE MULTI-VALUE OF EFFECTIVE NUCLEON MASS IN HOT/DENSE NUCLEAR MATTER AND THE PHASE TRANSITION
From the Lagrangian of QHD-I model, we investigate the effective nucleon mass under the mean field approximation in a wide temperature region. The multi-solution of self-consistent equation for the effective mass in found. In the high temperature region, the relation between the multi-solutions and the phase transition is analyzed. Furthermore, the variation of energy density in this region is studied.
119453402
1S0 pairing correlation in symmetric nuclear matter with Debye screening effects
Abstract The 1 S 0 pairing of symmetric nuclear matter is discussed in the framework of relativistic nuclear theory with Dyson–Schwinger equations (DSEs). The in-medium nucleon and meson propagators are treated in a more self-consistent way through meson polarizations. The screening effects on mesons due to in-medium nucleon excitation are found to reduce the 1 S 0 pairing gap and shift remarkably the gap peak to low density region.
118416435
Shear viscosity of a gluon plasma in perturbative QCD
Abstract We calculate the shear viscosity ( η ) to entropy density ( s ) ratio η / s of a gluon plasma in kinetic theory including the g g → g g and g g → g g g processes. Due to the suppressed contribution to η in the g g → g g forward scattering, it is known that the gluon bremsstrahlung g g ↔ g g g process also contributes at the same order ( O ( α s − 2 ) ) in perturbative QCD. Using the Gunion–Bertsch formula for the g g → g g g matrix element which is valid for the limit of soft bremsstrahlung, we find that the result is sensitive to whether the same limit is taken for the phase space. Using the exact phase space, the g g ↔ g g g contribution becomes more important to η than g g → g g for α s ≳ 2 × 10 − 3 . Therefore, at α s = 0.1 , η / s ≃ 1.0 , between 2.7 obtained by Arnold, Moore and Yaffe (AMY) and 0.5 obtained by Xu and Greiner (XG). If the soft bremsstrahlung limit is imposed on the phase space such that the recoil effect from the bremsstrahlung gluon is neglected, then the correction from the g g ↔ g g g process is about 10–30% of the total which is close to AMY's prediction. This shows that further studies beyond the soft bremsstrahlung approximation used by XG and collinear approximation used by AMY are needed.
119198603
Phase Transitions and the Perfectness of Fluids
We calculate the ratio eta/s, the shear viscosity (eta) to entropy density (s), which characterizes how perfect a fluid is, in weakly coupled real scalar field theories with different types of phase transitions. The mean-field results of the eta/s behaviors agree with the empirical observations in atomic and molecular systems such as water, He, N, and all the matters with data available in the NIST database. These behaviors are expected to be the same in N component scalar theories with an O(N) symmetry. We speculate these eta/s behaviors are general properties of fluid shared by QCD and cold atoms. Finally, we clarify some issues regarding counterexamples of the conjectured universal eta/s bound found in Refs.[16,17].
119272530
Model analysis of thermal UV-cutoff effects on the chiral critical surface at finite temperature and chemical potential
We study the effects of temporal UV-cutoff on the chiral critical surface in hot and dense QCD using a chiral effective model. Recent lattice QCD simulations indicate that the curvature of the critical surface might change toward the direction in which the first-order phase transition becomes stronger on increasing the number of lattice sites. To investigate this effect on the critical surface in an effective model approach, we use the Nambu-Jona-Lasinio model with finite Matsubara frequency summation. We find that the nature of the curvature of the critical surface does not alter appreciably as we decrease the summation number, which is unlike the case that was observed in recent lattice QCD studies. This may suggest that the dependence of chemical potential on the coupling strength or some additional interacting terms such as vector interactions could play an important role at finite density.
119512566
Drell-Hearn-Gerasimov sum-rule for the deuteron in nuclear effective field theory
Abstract The Drell–Hearn–Gerasimov sum rule for the deuteron is studied in nuclear effective field theory. The low-energy theorem for the spin-dependent Compton amplitude f 1 ( ω ) is derived to the next-to-leading order in low-energy expansion. The spin-dependent photo-disintegration cross-section σ P − σ A is calculated to the same order, and its contribution to the dispersive integral is evaluated.
122340199
Multijet and single diffraction dissociation Monte Carlo generator
We have built a Monte Carlo generator for simulating propagation of cosmic ray particles in the atmosphere. The core of the generator is ap-air nuclear interaction model in which SD and NSD processes are included in the inelastic collisions. Based on QCD partonic theory, multiple minijet production is described in detail in the NSD process. A phase-space model is used for the SD process in our work. This generator reproduces cosmic ray experimental data well at very high energies.