59485768
Microscopic description of spherical to γ-soft shape transitions in Ba and Xe nuclei
The rapid transition between spherical and γ-soft shapes in Ba and Xe nuclei in the mass region A>130 is analyzed using excitation spectra and collective wave functions obtained by diagonalization of a five-dimensional Hamiltonian for quadrupole vibrational and rotational degrees of freedom, with parameters determined by constrained self-consistent relativistic mean-field calculations for triaxial shapes. The results reproduce the characteristic evolution of excitation spectra and E2 transition probabilities, and in general, a good agreement with available data is obtained. The calculated spectra display fingerprints of a second-order shape phase transition that can approximately be described by analytic solutions corresponding to the E(5) dynamical symmetry.
101147336
Impedance Computation of Main Components in CSNS/RCS
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.
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.
33315431
Spin structure of nucleons in a quark model with constituent gluons.
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
119246486
Probing the symmetry energy with isospin ratio from nucleons to fragments
Within the framework of ImQMD05, we study several isospin sensitive observables, such as DR(n/p) ratios, isospin transport ratio (isospin diffusion), yield ratios for LCPs between the projectile region and mid-rapidity region for the reaction systems Ni+Ni, Zn+Zn, Sn+Sn at low-intermediate energies. Our results show that those observables are sensitive to the density dependence of symmetry energy, and also depend on the cluster formation mechanism. By comparing these calculations to the data, the information of the symmetry energy and reaction mechanism is obtained.
122275477
Analysis of intermediate energy proton-induced spallation reactions by an improved quantum molecular dynamics plus statistical decay model
Intermediate energy proton-induced spallation reactions with various targets are studied by the improved quantum molecular dynamics (ImQMD05) model incorporated with the statistical decay model. The influences of the different Skyrme interactions on the mechanism of spallation reaction and the double differential cross sections of emitted neutrons are studied. It is found that the different Skyrme interactions influence the low energy part of spectrum of emitted neutrons. This effect decreases as incident energy becomes higher. The double differential cross sections of emitted neutrons are found to be in good agreement with experimental data when the Skyrme parameter set SkP is adopted.
119563640
Microscopic description of quantum shape fluctuation in C isotopes
Covariant density functional theory is used to investigate quantum shape fluctuation in {sup 16}C and other even-even carbon isotopes. Long-range correlations beyond the mean-field approximation are taken into account by configuration mixing of wave functions with triaxial shapes and by restoring the spontaneously broken rotational symmetry through a three-dimensional angular-momentum projection. The systematics of the excitation energy of the 2{sub 1}{sup +} state and the B(E2:2{sub 1}{sup +}{yields}0{sub 1}{sup +}) values in carbon isotopes are reproduced rather well. Decoupled structures with rather different deformations for neutrons and protons have been found in {sup 16,18,20}C. In addition, the effects of shape fluctuations in {beta} and {gamma} deformations on the low-lying excited states of these nuclei are examined.
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.
9051613
Mass and isotope dependence of limiting temperatures for hot nuclei
The mass and isotope dependence of limiting temperatures for hot nuclei are investigated. The predicted mass dependence of limiting temperatures is in good agreement with data derived from the caloric curve data. The predicted isotope distribution of limiting temperatures appears to be a parabolic shape and its centroid is not located at the isotope on the beta-stability line (T=0) but at neutron-rich side. Our study shows that the mass and isotope dependence of limiting temperatures depend on the interaction and the form of surface tension and its isospin dependence sensitively.