An Investigation of Relativistic Microscopic Optical Potential in Terms of Relativistic Brueckner-Bethe-Goldstone Equation

Relativistic microscopic optical potential of nucleon-nucleus is derived from the relativistic Brueckner-Bethe-Goldstone (RBBG) equation.The complex effective mass of a nucleon is determined by a fit to 200MeV p-⁴⁰Ca scattering data.The relativistic microscopic optical potentials with this effective mass are obtained from RBBG for p-¹⁶O,⁴⁰Ca,⁹⁰Zr and ²⁰⁸Pb scattering in energy range from 160 to 180MeV.The microscopic optical potential is used to study the proton-⁴⁰Ca scattering problem at 200MeV.The results,such as defferential cross section,analyzing power and spin rotation function are compared with those calculated from phenomenological relativistic optical potential.     

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.     

Temperature Dependent Relativistic Microscopic Optical Potential and Mean Free Paths of Nucleons

The microscopic optical potential,mean free paths and Schrodinger equivalent potential of nucleons at finite temperature in nuclear matter are studied based on Walecka's model and thermo field dynamics.We let only the Hartree-Fock self-energy of nucleon represent to be the real part of the microscopic optical potential and the fourth order of meson exchange diagrams,i.e. the core polarization represent the imaginary part of microscopic optical potential in nuclear matter.The microscopic optical potential of finite nuclei is obtained with the local density approximation.     

The Contribution of the Fourth Order Exchange Diagrams to The Relativistic Microscopic Optical Potential

The contribution of the fourth order exchange diagrams is first studied to the imaginary part of nucleon self-energy,the relativistic microscopic optical potential and the Schrodinger equivalent potential of the relativistic microscopic optical potential based on Walecka's meson-nucleon model.     

Neutron Relativistic Phenomenological and Microscopic Optical Potentials

The experimental data of the neutron total cross section σ_t,nonelastic cross section σ_non and elastic scattering angular distribution σ_el(θ) for ten target nuclei ranging from ¹²C to ²³⁸U with incident energies E_n=20—1000MeV were used to optimize the relativistic phenomenological optical potential (RPOP) through automatic search of the best parameters by computer.In addition,a relativistic microscopic optical potential (RMOP) based on Walecka model were also used to analyze the same data and compare with the RPOP.
Through comparison between these two kinds of relativistic optical potential hints in improving both the RMOP and RPOP is indicated.     

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.     

Second Order Correction of Relativistic Optical Potential

The imaginary part of the off-energy shell optical potential of a nucleon in nuclear matter, where the polarization and correlation contribution of the exchanges of the σ and ω mesons are taken into account, is derived in the framework of the relativistic meson-nucleon field theory. The second order correction of the real part of the optical potential is calculated in terms of the dispersion relation and the effective mass of a nucleon in the nuclear medium is also investigated in this paper.     

A Microscopic Optical Potential for Deuteron

The microscopic optical potential for deuteron is obtained by folding the microscopic optical potentials of its constituent nucleons. The optical potential is used to predict the reaction cross sections and the elastic scattering angular distributions for some spherical target nuclei, and the results of theoretical calculation are compared with the experimental data available.     

The Effect of Interaction Range in Relativistic Microscopic Optical Potentials

Starting from the Walecka model about relativistic nucleon-meson field theory,the effect of interaction range in the relativistic microscopic optical potentials for nucleon-nucleus is included by folding the optical potentials in Local Density Approximity with nucleon-nucleon interaction potentials from the Walecka model.The present potentials are used to analyze the proton elastic scattering from nuclei.The agreement of the present calculation with experiment data is better than that of LDA.     

Analyses of Relativistic Optical Potential for Medium Energy Proton

The influence of the parameters of the relativistic optical potential on the nucleon scattering properties,such as cross sections,angular distributions and spin observables etc.,is studied based on a set of global Dirac phenomenological optical potentials.It is shown that,in contrast with the case at low energies.the total scattering cross sections vary slowly as the energy and weakly depend on the potentials at E_p<200MeV.The differential cross sections and spin observables depend not only on the volume integrals of the optical potentials,but also on their strengths and shapes.The applicability of the relativistic microscopic optical potentia based on Walecka model in the medium energy region is also discussed in this paper.     

Self-Consistent Approximations in Relativistic Plasmas: Quasiparticle Analysis of the Thermodynamic Properties

We generalize the concept of conserving, Φ-derivable, approximations to relativistic field theories. Treating the interaction field as a dynamical degree of freedom, we derive the thermodynamic potential in terms of fully dressed propagators, an approach which allows us to resolve the entropy of a relativistic plasma into contributions from its interacting elementary excitations. We illustrate the derivation for a hot relativistic system governed by electromagnetic interactions.     

Quantum Potential in Relativistic Dynamics

The experimental confirmation of nonlocality has renewed interest in Bohm's quantum potential. The construction of quantum potentials for relativistic systems has encountered difficulties which do not arise in a parametrized formulation of relativistic quantum mechanics known as Relativistic Dynamics. The purpose of this paper is to show how to construct a quantum potential in the relativistic domain by deriving a relativistically invariant quantum potential using Relativistic Dynamics. The formalism is applied to three relativistic scalar particle models: a single particle interacting with a scalar potential; N particles interacting with a scalar potential; and a single particle interacting with an electromagnetic 4-vector potential.     

Thermodynamic Potential of Relativistic Electron Plasma

Within the real time formalism of quantum field theory at finite temperatures based on the closed-time-path Green's function approach, a closed analytical expression of the thermodynamic potential of a relativistic electron plasma is derived under the random phase approximation by summing up all ring diagrams. The result is natural extension to the relativistic case sf our previous formula derived in the case of a Coulomb gas.     

Relativistic Morse Potential and Tensor Interaction

In this paper, by applying the Pekeris approximation, we present solutions of the Dirac equation for the Morse potential including a Coulomb-like tensor potential with arbitrary spin-orbit coupling number κ under spin and pseudospin symmetry limits. The generalized parametric Nikiforov–Uvarov method is used to obtain energy eigenvalues and corresponding eigenfunctions in their closed forms. We show that tensor interaction removes degeneracies between spin and pseudospin doublets. Some numerical results are given, too.     

Relativistic Scattering States of Coulomb Potential Plus a New Ring-Shaped Potential

In this paper, exact solutions of scattering states of the Klein-Gordon equation with Coulomb potential plus a new ring-shaped potential are studied under the condition that the scalar potential is equal to the vector potential. The normalized wave functions of scattering states on the “k/2π scale” and the calculation formula of phase shifts are presented. Analytical properties of the scattering amplitude are discussed.     

Relativistic New Yukawa-Like Potential and Tensor Coupling

We approximately solve the Dirac equation for a new suggested generalized inversely quadratic Yukawa potential including a Coulomb-like tensor interaction with arbitrary spin-orbit coupling quantum number ${\kappa}$ . In the framework of the spin and pseudospin (p-spin) symmetry, we obtain the energy eigenvalue equation and the corresponding eigenfunctions, in closed form, by using the parametric Nikiforov–Uvarov method. The numerical results show that the Coulomb-like tensor interaction, ?T/r, removes degeneracies between spin and p-spin state doublets. The Dirac solutions in the presence of exact spin symmetry are reduced to Schr?dinger solutions for Yukawa and inversely quadratic Yukawa potentials.     

Spin Symmetry in the Relativistic q-Deformed Morse Potential

In this paper, we investigate the spin symmetry case of a spin ${-\frac{1}{2}}$ particle governed by a q-deformed Morse potential by presenting an approximate bound-state solutions of the Dirac equation with the spin-orbit coupling term for spin symmetry vector and scalar q-deformed Morse potential within framework of the Pekeris approximation. The relativistic energy levels are obtained using the Nikiforov–Uvarov (NU) method and the two-components spinor wave functions are obtain in terms of the Jacobi polynomials. It is found that there exist only positive-energy for the bound states of some diatomic molecules under spin symmetry.     

Optical Polarization Radiation of Relativistic Electrons in Conducting Targets

A theoretical model and results of experiments on optical polarization radiation of relativistic electrons from conducting targets performed on the synchrotron and microtron of Nuclear Physics Institute at Tomsk Polytechnic University are reported. The measurements of spectral characteristics of resonance polarization radiation in periodic targets over a wide range of electron energies (both in the Smyth–Purcell geometry and for different angles between the targets and the direction of the electron beam) show reasonable agreement with theoretical estimates.