118413215
Energy-dependent Lorentz covariant parameterization of the NN interaction between 50 and 200 MeV
For laboratory kinetic energies between 50 and 200 MeV, we focus on generating an energy-dependent Lorentz covariant parametrization of the on-shell nucleon-nucleon (NN) scattering amplitudes in terms of a number of Yukawa-type meson exchanges in first-order Born approximation. This parametrization provides a good description of NN scattering observables in the energy range of interest, and can also be successfully extrapolated to energies between 40 and 300 MeV.
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.
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.
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
101147336
Impedance Computation of Main Components in CSNS/RCS
118367915
Constraint on nuclear symmetry energy from nuclear charge dependent neutron skin thickness of nuclei
An alternative way to constrain the density dependence of the symmetry energy with the slope of the neutron skin thickness of nuclei which shows a linear relation to both the isospin asymmetry and the nuclear charge with a form of Z^{2/3} is proposed. The linear dependence of the neutron skin thickness on the nuclear charge and isospin asymmetry is systematically studied with the data from antiprotonic atom measurement experimentally and the extended Thomas-Fermi approach incorporated the Skyrme energy density functional theoretically. An obviously linear relationship between the slope parameter L of the symmetry energy and the slope of the neutron skin thickness on the isospin asymmetry can be found by adopting 66 Skyrme interactions in the calculation. Combining the available experimental data, the constraint of 16<L<66 MeV on the slope parameter of the symmetry energy is obtained. The Skyrme interactions satisfying the constraint are selected.
118996027
Production and rescattering of strange baryons at SPS energies in a transport model with hadron potentials
A mean-field potential version of the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model is used to investigate the production of strange baryons, especially the $\Lambda$s and $\overline{\Lambda}$s, from heavy ion collisions at SPS energies. It is found that, with the consideration of both formed and pre-formed hadron potentials in UrQMD, the transverse mass and longitudinal rapidity distributions of experimental data of both $\Lambda$s and $\overline{\Lambda}$s can be quantitatively explained fairly well. Our investigation also shows that both the production mechanism and the rescattering process of hadrons play important roles in the final yield of strange baryons.
4046382
Nuclear symmetry potential in the relativistic impulse approximation
Using the relativistic impulse approximation with the Love-Franey NN scattering amplitude developed by Murdock and Horowitz, we investigate the low-energy (100{<=}E{sub kin}{<=}400 MeV) behavior of the nucleon Dirac optical potential, the Schroedinger-equivalent potential, and the nuclear symmetry potential in isospin asymmetric nuclear matter. We find that the nuclear symmetry potential at fixed baryon density decreases with increasing nucleon energy. In particular, the nuclear symmetry potential at saturation density changes from positive to negative values at nucleon kinetic energy of about 200 MeV. Furthermore, the obtained energy and density dependence of the nuclear symmetry potential is consistent with those of the isospin- and momentum-dependent MDI interaction with x=0, which has been found to describe reasonably well both the isospin diffusion data from heavy-ion collisions and the empirical neutron-skin thickness of {sup 208}Pb.
118612358
THE CARNEGIE-IRVINE GALAXY SURVEY. III. THE THREE-COMPONENT STRUCTURE OF NEARBY ELLIPTICAL GALAXIES
Motivated by recent developments in our understanding of the formation and evolution of massive galaxies, we explore the detailed photometric structure of a representative sample of 94 bright, nearby elliptical galaxies, using high-quality optical images from the Carnegie-Irvine Galaxy Survey. The sample spans a range of environments and stellar masses, from M * = 1010.2 to 1012.0 M ☉. We exploit the unique capabilities of two-dimensional image decomposition to explore the possibility that local elliptical galaxies may contain photometrically distinct substructure that can shed light on their evolutionary history. Compared with the traditional one-dimensional approach, these two-dimensional models are capable of consistently recovering the surface brightness distribution and the systematic radial variation of geometric information at the same time. Contrary to conventional perception, we find that the global light distribution of the majority (75%) of elliptical galaxies is not well described by a single Sersic function. Instead, we propose that local elliptical galaxies generically contain three subcomponents: a compact (Re 1 kpc) inner component with luminosity fraction f 0.1-0.15; an intermediate-scale (Re 2.5 kpc) middle component with f 0.2-0.25; and a dominant (f = 0.6), extended (Re 10 kpc) outer envelope. All subcomponents have average Sersic indices n 1-2, significantly lower than the values typically obtained from single-component fits. The individual subcomponents follow well-defined photometric scaling relations and the stellar mass-size relation. We discuss the physical nature of the substructures and their implications for the formation of massive elliptical galaxies.
119441908
Dynamical isospin effects in nucleon-induced reactions
The isospin effects in proton-induced reactions on isotopes of $^{112\ensuremath{-}132}\mathrm{Sn}$ and the corresponding $\ensuremath{\beta}$-stable isobars are studied by means of the improved quantum molecular dynamics model and some sensitive probes for the density dependence of the symmetry energy at subnormal densities are proposed. The beam energy range is chosen to be 100\char21{}300 MeV. Our study shows that the system size dependence of the reaction cross sections for $p+{}^{112\ensuremath{-}132}\mathrm{Sn}$ deviates from the Carlson's empirical expression obtained by fitting the reaction cross sections for proton on nuclei along the $\ensuremath{\beta}$-stability line and sensitively depends on the stiffness of the symmetry energy. We also find that the angular distribution of elastic scattering for $p+{}^{132}\mathrm{Sn}$ at large impact parameters is very sensitive to the density dependence of the symmetry energy, which is uniquely due to the effect of the symmetry potential with no mixture of the effect from the isospin dependence of the nucleon-nucleon cross sections. The isospin effects in neutron-induced reactions are also studied and it is found that the effects are just opposite to that in proton-induced reactions. We find that the difference between the peaks of the angular distributions of elastic scattering for $p+{}^{132}\mathrm{Sn}$ and $n+{}^{132}\mathrm{Sn}$ at ${E}_{p,n}=100$ MeV and $b=7.5$ fm is positive for soft symmetry energy ${U}_{\mathrm{sym}}^{\mathrm{sf}}$ and negative for super-stiff symmetry energy ${U}_{\mathrm{sym}}^{\mathrm{nlin}}$ and close to zero for linear density dependent symmetry energy ${U}_{\mathrm{sym}}^{\mathrm{lin}}$, which seems very useful for constraining the density dependence of the symmetry energy at subnormal densities.