17720256
Kaon productions off nucleons and the structure of baryon resonances
The recent investigations in the chiral quark model show that kaon productions of nucleons play an important role in understanding the structure of baryons. The evidences of a third S11 resonance in the second resonance region and two narrow states around 2 GeV suggest a set of the molecular type baryons with the hidden strangeness. Confirming these states requires further theoretical and experimental studies of the strangeness production.
16718501
The Kaon-Photoproduction Of Nucleons In The Chiral Quark Model
In this paper, we develop a general framework to study the mesonphotoproductions of nucleons in the chiral quark model. The S and U channel resonance contributions are expressed in terms of the ChewGoldberger-Low-Nambu (CGLN) amplitudes. The kaon-photoproduction processes, γp → K+Λ, γp → K+Σ0, and γp → K0Σ+, are calculated. The initial results show that the quark model provides a much improved description of the reaction mechanism for the kaon-photoproductions of the nucleon with less parameters than the traditional phenomenological approaches. PACS numbers: 13.75.Gx, 13.40.Hq, 13.60.Le,12.40.Aa
120492049
Octupole degree of freedom for nuclei near 152Sm in a reflection-asymmetric relativistic mean-field approach
The potential energy surfaces of even-even isotopes near 152Sm are investigated within the constrained reflection-asymmetric relativistic mean-field approach using parameter sets PK1 and NL3. It is shown that the critical-point candidate nucleus 152Sm marks the shape/phase transition not only from U(5) to SU(3) symmetry, but also from the octupole deformed ground state in 150Sm to the quadrupole deformed ground state in 154Sm. The important role of the octupole deformation driving pair (?2f7/2, ?1i13/2) is demonstrated based on the components of the single-particle levels near the Fermi surface. In addition, the patterns of both the proton and the neutron octupole deformation driving pairs (?2f7/2, ?1i13/2) and (?2d5/2, ?1h11/2) are investigated.
101147336
Impedance Computation of Main Components in CSNS/RCS
33315431
Spin structure of nucleons in a quark model with constituent gluons.
119334067
Longitudinal transitions of baryon resonances in the constituent quark model
A longitudinal transition operator that satisfies the gauge invariance requirement is introduced in the constituent quark model. The corresponding longitudinal transitions from the ground state of the nucleon to resonances of the baryon are calculated. The study shows that the longitudinal coupling plays an important role in the understanding of the structure of the baryon.
56465847
Effect of isospin-dependent cluster recognition on the observables in heavy ion collisions
We introduce isospin dependence in the cluster recognition algorithms used in the quantum molecular dynamics model to describe fragment formation in heavy ion collisions. This change reduces the yields of emitted nucleons and enhances the yields of fragments, especially heavier fragments. The enhancement of neutron-rich lighter fragments mainly occurs at midrapidity. Consequently, isospin-dependent observables, such as isotope distributions, yield ratios of n/p, t/ 3 He, and isoscaling parameters are affected. We also investigate how equilibration in heavy ion collisions is affected by this change.
121145994
Nuclear matter saturation point and symmetry energy with modern nucleon-nucleon potentials
We determine the saturation properties of nuclear matter within the Brueckner-Hartree-Fock approach based on a large set of modern nucleon-nucleon potentials and confirm the validity of the Coester band. The improvement of the saturation point when including nuclear three-body forces is pointed out and comparison with the Dirac-Brueckner-Hartree-Fock results is made.
118197616
Transition to Delta matter from hot, dense nuclear matter within a relativistic mean field formulation of the nonlinear sigma and omega model
An investigation of the transition to $\ensuremath{\Delta}$ matter is performed based on a relativistic mean field formulation of the nonlinear $\ensuremath{\sigma}$ and $\ensuremath{\omega}$ model. We demonstrate that in addition to the $\ensuremath{\Delta}$-meson coupling, the occurrence of the baryon resonance isomer also depends on the nucleon-meson coupling. Our results show that for the favored phenomenological value of ${m}^{*}$ and $K$, the $\ensuremath{\Delta}$ isomer exists at baryon density $\ensuremath{\sim}2$--3${\ensuremath{\rho}}_{0}$ if $\ensuremath{\beta}$=1.31 is adopted. For universal coupling of the nucleon and $\ensuremath{\Delta}$, the $\ensuremath{\Delta}$ density at baryon density $\ensuremath{\sim}2$--3${\ensuremath{\rho}}_{0}$ and temperature $\ensuremath{\sim}0.4$--0.5 fm${}^{\ensuremath{-}1}$ is about normal nuclear matter density, which is in accord with a recent experimental finding.
119107991
Transport model study of nuclear stopping in heavy-ion collisions over the energy range from 0.09A to 160A GeV
Nuclear stopping in heavy-ion collisions over a beam energy range from SIS and AGS up to SPS is studied in the framework of the modified Ultrarelativistic Quantum Molecular Dynamics transport model, in which mean field potentials of both formed and "preformed" hadrons (from string fragmentation) and medium-modified nucleon-nucleon elastic cross sections are considered. It is found that nuclear stopping is influenced by both the stiffness of the equation of state and medium modifications of nucleon-nucleon cross sections at SIS energies. At high SPS energies, a two-bump structure is shown in the experimental rapidity distribution of free protons, which can be understood by considering the preformed hadron potentials.
118014681
Towards a Self-Consistent Description of the Relativistic Boltzmann-Uehling-Uhlenbeck Approach
The heavy ion collisions (HIC) provide a unique opportunity to study the time evolution process of nuclear matter under violent collisions as well as nuclear properties under extreme conditions of high density and temperature. However, the interesting informations on these problems can only be obtained indirectly through certain theoretical models. Thus, one has to choose a good theoretical tool, which should be as general and basic as possible on the one hand and as practicable as possible on the other hand. The most ambitious one is to obtain the relativistic transport equation starting from the time dependent Bruckner G-matrix theory1. In this approach the time evolution of the HIC process is described by relativistic kinetic equation and the G-matrix served as a dynamical input of the two body interaction. Therefore, to acquire complete numerical solution will be very difficult and till now there has no real calculation which fulfills this requirement.