120267358
The UV‐Cutoff Effects on the Chiral Critical Surface in Hot and Dense QCD
The search of the QCD critical point is one of the interesting issues both in theoretical and experimental particle physics. In this article, we use the Nambu Jona‐Lasinio model to study the UV‐cutoff effects on the critical surface which may play a crucial role to the possible existence/non‐existence of the critical point. Then we compare the indications between the results obtained through our effective approach and the lattice QCD simulations.
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.
119491739
Twisted valence quarks and hadron interactions on the lattice
Abstract We consider QCD with valence and sea quarks obeying different boundary conditions. We point out that the energy of low lying two hadron states do not depend on the boundary condition of the sea quarks (up to exponentially small corrections). Thus, the advantages in using twisted boundary conditions on the lattice QCD extraction of nucleon–nucleon phase shifts can be gained without the need of new gauge configurations, even in fully unquenched calculations.
13534760
Constructing parton convolution in effective field theory.
Parton convolution models have been used extensively in describing the sea quarks in the nucleon and explaining quark distributions in nuclei (the EMC effect). From the effective field theory point of view, we construct the parton convolution formalism which has been the underlying conception of all convolution models. We explain the significance of scheme and scale dependence of the auxiliary quantities such as the pion distributions in a nucleon. As an application, we calculate the complete leading nonanalytic chiral contribution to the isovector component of the nucleon sea.
119519405
Parity Violation in Polarized-Gamma Proton Compton Scattering
Polarized beam gamma p Compton scattering provides a theoretically clean way to extract the isovector parity violating pion-nucleon coupling constant $h_{\pi NN}^{(1)}$. This channel is more tractable experimentally than the recently proposed extraction of $h_{\pi NN}^{(1)}$ from the Bedaque-Savage process --- polarized target gamma p compton scattering. The leading parity violating effect is calculated using Heavy Baryon Chiral Perturbation Theory. The size of the asymmetry is estimated to be ~ 4 10^{-8} for 120 MeV photon energy.
119418730
Large-Nc quark distributions in the delta and chiral logarithms in quark distributions of the nucleon
Abstract In a world with two quark flavors and a large number of colors ( N c ), the polarized and unpolarized quark distributions in the delta are completely determined by those in the nucleon up to relative O (1/N c 2 ) . In particular, we find q Δ (x)=[(1±2T z )u N (x)+(1∓2T z )d N (x)]/2(1+ O (1/N c 2 )) and Δq Δ (x)=[(5±2T z )Δu N (x)+(5∓2T z )Δd N (x)]/10(1+ O (1/N c 2 )) , where q = u , d and T z the charge state of a delta. The result can be used to estimate the leading chiral-logarithmic corrections to the quark distributions in the nucleon.
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.
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.
121652117
The L-G Phase Transition and the Nucleon–Nucleon Interaction Potential within QHD-I Model
The nucleon–nucleon interaction potential in hot/dense nuclear matter is studied within the QHD-I model. We find that a Yukawa potential, which contains attractive and repulsive terms, acting between nucleons is modified by the variation of the Debye mass. In particular, a nucleon system described by this Yukawa potential will be unbound at some critical T and μ. The critical point is very close to that of the L-G phase transition given in the literatures.
119072276
Quantum rearrangement and self-consistent BCS-BEC crossover thermodynamics
Based on previous works, analytical calculational procedures for dealing with the strongly interacting fermion ground state are further developed through a medium-dependent potential in terms of the Bethe-Peierls contact interaction model. The methods are exact in the unitary limit regime and they lead to self-consistent equations analogous to the Hartree ones. The single particle energy spectrum rearrangement effects on the thermodynamics due to the Hugenholtz\char21{}van Hove theorem constraint are addressed. These effects lead to an additional instantaneous correlation potential contribution to the system physical chemical potential and pressure, i.e., equation of state, in order to enforce the classical thermodynamic consistency. The Dyson-Schwinger equations represent implicitly the various Bethe-Goldstone expansion ones. In a thermodynamically self-consistent way, the universal dimensionless factor is analytically calculated to be $\ensuremath{\xi}=\frac{4}{9}$, which defines the ratio of the unitary fermions energy density to that of the ideal noninteracting ones at $T=0$.