Temperature-Dependent Imaginary Part of the Off-Shell Nucleon Self-Energy and the Second Order Correction of Real Part of the Nucleon Self-Energy

The imaginary part of the off-shell nucleon self-energy at finite temperature in nuclear matter, where the polarization and correlation contributions of exchanges of the meson are taken into account, is investigated based on Walecka's meson-nucleon model and thermofield dynamics. The second order correction of temperature-dependent real part of the nucleon self-energy is calculated in terms of the dispersion relation. The Schrodinger equivalent potential of relativistic microscopic optical potential of a nucleon at finite temperature in nuclear medium is also studied.     

Nucleon-nucleus optical potential at finite temperatures within a semimicroscopic approach for the case of Skyrme forces

Within the nuclear-matter approximation, the local-density approximation, and perturbation theory, an approach to constructing a microscopic nucleon-nucleus optical potential at finite nuclear temperatures is developed on the basis of effective density-dependent nucleon-nucleon forces. The real and the imaginary part of the neutron-nucleus optical potential and the mean free paths of neutrons in nuclear matter are calculated at various neutron energies and various nuclear temperatures. The effect of the inclusion of the rearrangement potential on the quantities under consideration is studied, and its importance is demonstrated.     

SEMI-MICROSCOPIC OPTICAL POTENTIAL CALCULATION BY THE NUCLEAR MATTER APPROACH——I. SYMMETRIC NUCLEAR MATTER

In this paper semi-microscopic nuclear matter approach is introduced to calculatethe microscopic optical potential. The first and second order mass operator in sym-metric nuclear matter is derived with Skyrme effective interactions and the real andimaginary part of the optical potential for finite nuclei is obtained by applying alocal density approximation. The five kinds of the different parameters of Skyrmeinteractions Ⅱ-Ⅵ are used and compared with the experimental data to study how wellthese Skyrme interactions can work for our purposes. Our results obtained in such asimple way seem to be to some extent comparable with those obtained with "nuclearmatter approach" and "nuclear structure approach" without adjusting the parame-ters of the Skyrme interactions so far.     

Semi-microscopic optical potential calculation by the nuclear matter approach

In this paper the semi-microscopic nuclear matter approach has been introduced to calculate the microscopic optical potential. The first- and second-order mass operators in asymmetric nuclear matter have been derived with Skyrme effective interactions and the real and imaginary parts of the optical potential for finite nuclei have been obtained by applying a local density approximation. Five Skyrme interactions II–VI have been used and compared with the experimental data to determine how well these Skyrme interaction function for our purposes. Our results obtained in this simple way are to some extent comparable with those obtained with the “nuclear matter” and “nuclear structure” approaches without adjusting the parameters of the Skyrme interactions.     

核子相对论微观光学势、薛定谔等效势和平均自由程对核密度及温度的依赖关系

在Walecka模型的基础上,应用热动力学理论和Dirac-Bruckner-Hartree-Fock方法,研究了有限温度不同密度下核子相对论微观光学势及其相应的薛定谔等效势和平均自由程.计算结果表明,核子薛定谔等效势和平均自由程对核密度的依赖相当敏感,当核密度增大时对核密度的依赖变得更为敏感.     

与核密度及温度相关的核子相对论微观光学势

在Walecka模型、热场动力学和相对论Dirac-Bruckner-Hartree-Fock计算结果基础上,研究了在不同核密度和各种温度情况下的核子相对论微观光学势及其相应的薛定谔等效势和平均自由程,计算结果表明,对于不同的温度,核子的薛定谔等效势与平均自由程随核密度变化较为敏感,而核温度对核子的薛定谔等效势和平均自由程的影响随着核密度的增加变大.     

A METHOD FOR THE CALCULATIONS OF THE NUCLEON-NUCLEUS MICROSCOPIC OPTICAL POTENTIAL

A method for the calculations of the nucleon-nucleus microscopic optical potential based on. various kindsof Skyrme force has been introduced. The first- and secondrordermass operators,in asymmetric nuclear matter have been derived and the real and imaginary parts of the optical potentialEfor finite nuclei have been obtained by applying a local density approximation. The. spin-crbit potential has also been obtained approximately. In most cases the expressions are analytical. The calculation results for some sets.of Skyrme forces.are in good agreement with the-empirical values and experiments.     

Heavy-ion optical potentials at finite temperature calculated using a complex effective interaction derived from a realistic force

Hot density distributions of heavy ions generated by a modified Thomas-Fermi calculation at finite temperature are used to calculate the optical potential using the double-folding method and a complex effective energy and density-dependent interaction deduced from a realistic NN (Reid soft-core) force in nuclear matter. The real and the imaginary part of the optical potential become more attractive when the temperature increases.     

Isospin-dependent relativistic microscopic optical potential in the Dirac Brueckner-Hartree-Fock method

There is growing evidence to suggest that the binding energy of nucleon in nuclear matter comes from a cancellation between large Lorentz scalar and vector potentials[1,2]. The relativistic approach has been of a great success in describing not only the ground state properties of stable nuclei, but also those of exotic nuclei. In the relativistic frame, the spin-orbit coupling can be deduced automatically, which is usually given by hand in the non-relativistic approach. The relativistic method…     

Some Aspects of Nuclear Structure in Relativistic Approach

The nucleon effective interaction in the nuclear medium is investigated in the framework of the DiracBrueckner-Hartree-Fock (DBHF) approach. A new decomposition of the Dirac structure of nucleon self-energy in the DBHF is adopted for asymmetric nuclear matter. The properties of finite nuclei are investigated with the nucleon effective interaction. The agreement with the experimental data is satisfactory. The relativistic microscopic optical potential in asymmetric nuclear matter is investigated in the DBHF approach. The proton scattering from nuclei is calculated and compared with the experimental data. A proper treatment of the resonant continuum for exotic nuclei is studied. The width effect of the resonant continuum on the pairing correlation is discussed. The quasiparticle relativistic random phase approximation based on the relativistic mean-field ground state in the response function formalism is also addressed.     

Some Aspects of Nuclear Structure in Relativistic Approach

The nucleon effective interaction in the nuclear medium is investigated in the framework of the DiracBrueckner-Hartree-Fock (DBHF) approach. A new decomposition of the Dirac structure of nucleon self-energy in the DBHF is adopted for asymmetric nuclear matter. The properties of finite nuclei are investigated with the nucleon effective interaction. The agreement with the experimental data is satisfactory. The relativistic microscopic optical potential in asymmetric nuclear matter is investigated in the DBHF approach. The proton scattering from nuclei is calculated and compared with the experimental data. A proper treatment of the resonant continuum for exotic nuclei is studied. The width effect of the resonant continuum on the pairing correlation is discussed. The quasiparticle relativistic random phase approximation based on the relativistic mean-field ground state in the response function formalism is also addressed.     

相对论微观光学势中的同位旋相关项

采用Dirac Brueckner-Hartree-Fock方法研究同位旋相关的相对论微观光学势, 讨论了其同位旋相关项的处理.采用定域密度近似得到有限核的微观光学势, 以²⁰⁸Pb为例讨论了光学势的同位旋相关性,并与唯象的Lane势进行了比较.     

Optical potential and nuclear matter

The relation of the parameters of the optical nucleon-nucleus potential to the characteristics of nuclear matter is established. The existing values of the parameters of the optical potential reflect well the binding energy per nucleon and the symmetry energy of nuclear matter. It is shown that the theorem of Hugenholtz and van Hove is not valid for the real part of the optical potential.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 97–100, January, 1978.     

Partial wave contributions to the antikaon potential at finite momentum

The momentum dependence of the antikaon optical potential in nuclear matter is obtained from a microscopic and self-consistent calculation using the meson-exchange Jülich interaction. Two self-consistent schemes are discussed, which would lead to substantially different predictions for the width of nuclear bound states. The effect of higher partial waves of the interaction, beyond the L=0 component, is studied and found to have moderate but nonnegligible effects on the nuclear potential at zero momentum. At momenta as large as 500 MeV/c, relevant in the analysis of heavy-ion collisions, the higher partial partial waves modify the optical potential by nearly a factor of two.     

On the nuclear matter approach to the heavy-ion optical potential

A simple theory of the heavy-ion optical potential oV, based on the local density approximation, is presented. The colliding ions are described locally as two slabs of nuclear matter. The real part of the energy density of the two slabs is derived from the properties of nuclear matter, and for the imaginary part the “frivolous model” is applied. Results for oV in the case of two slabs are presented and compared with results of other calculations. Arguments are given in favour of using the frivolous model in the optical potential and the VUU calculations for heavy-ion collisions.     

SELF-CONSISTENT SEMICLASSICAL APPROACH AND MICROSCOPIC OPTICAL POTENTIALS AT FINITE TEMPERATURE:II THE IMAGINARY PART

Based on the finite temperature self-consistent semiclassical (FTSCSC) approach and the local density approximation (LDA),the imaginary part of the microscopic nucleon-nucleus optical potential is evaluated and discussed.This work indicates the necessity of using temperature dependent nucleon density in dealing with optical potentials at finite temperature.     

Semiclassical expansion of the microscopic nucleon-nucleus optical potential

A semiclassical expansion is given for the microscopic optical potential in ladder-type approximations. The problem has been approached by starting with the formulation of the optical potential within the Green's function scheme. By a reordering of the WignerKirkwood expansion it has been possible to obtain a general expansion, which agrees in zeroth order with the standard nuclear matter approach. The next order, which we discuss in more detail, contains the curvature corrections.     

Effect of three-body interaction on hot asymmetric nuclear matter

The properties of hot asymmetric nuclear matter are studied in the framework of the finite temperature Brueckner－Hartree－Fock theory that is extended to include the contribution of microscopic three-body forces. We give the variation of the critical temperature with the asymmetry parameter and show the effect brought by this three-body repulsive potential on the value of the critical asymmetry of the phase transition for asymmetric nuclear matter. Owing to the additional repulsion provided by three-body forces, this value decreases. In addition, the domain of mechanical instability for hot nuclear matter is also indicated, which gradually shrinks with increasing asymmetry and temperature.     

The single particle potential in nuclear matter

The energy dependent real part of the optical potential for particles and holes in nuclear matter is calculated from a realistic nuclear hamiltonian that explains the nucleon-nucleon scattering data and equilibrium properties of nuclear matter. The variational method is used with Fermi-hypernetted and single-operator-chain summation techniques. The results are comparable with empirical Woods-Saxon well depths at energies ? 150 MeV. At higher energies the potential has a density dependence suggesting a “wine-bottle” shaped nucleon-nucleus potential.