A multichannel quasi-separable potential approach to nucleon-nucleus scattering

A quasi-separable potential model for two-body multichannel scattering is developed. Spin and Coulomb effects are taken into account. By a suitable choice of the separable nuclear interactions we arrive at simple analytic expressions for the transition amplitudes. Our model is applied to the study of the n-¹²C and p-¹²C scattering processes. Effects arising from the excitation of the target nucleus are well reproduced.     

Relativistic light-cone approach to elastic electron-deuteron scattering

The connection between light-cone dynamics and field theory is analyzed in detail within the zero-range approximation, with particular attention to the so-called angular condition. New and detailed calculations for the elastic form factors of the deuteron are presented for the Bonn, Paris, Reid Soft-Core, Argonne V14 and one-pion-exchange potentials with various choices of the electromagnetic form factors of the nucleon.     

Pionization effects in nucleon-nucleus scattering

A simple unitary model for meson production in nucleon-nucleon scattering is extended to nucleon-nucleus scattering. In the high energy limit the produced mesons remain coherent with the projectile over the entire depth of the nucleus and tend to increase the total cross sections. A crude estimate of the size of the effect gives an increase of the total cross section for proton-deuteron scattering of 13 mb at NAL energies.     

Description of nucleon-nucleus scattering in the Dirac-Brueckner method

Elastic scattering of protons from nuclei is studied based on the Dirac-Brueckner approach. Effective N-N interactions in the nuclear medium are obtained by solving the relativistic Brueckner-Bethe-Goldstone equation in infinite nuclear matter. Relativistic optical potentials for p-⁴⁰Ca scattering at 200 MeV are calculated in the improved local density approximation. It is found that medium effects other than Pauli blocking reduce the strengths of scalar and vector potentials very much. Differential cross section and spin observables are calculated and compared with experimental data.     

Medium corrections in intermediate-energy nucleon-nucleus scattering

Medium corrections in elastic and inelastic nucleon-nucleus scattering are discussed in the framework of Watson's multiple scattering theory. We derive formulae for the effective interactions to be used in the calculation of elastic and inelastic scattering based on a consistent local-density approximation. We show the numerical results of analyses of the p + ¹⁶O reaction at E_p = 135 MeV.     

A separable potential approach to nucleon-nucleus scattering with exact treatment of Coulomb interactions

A suitable, physically reasonable choice of separable nucleon-nucleus potential is made, which leads to very simple analytic expressions for the form factors in the Coulomb-state representation. This allows one to take account of Coulomb effects in an exact and simple way. The model is applied to the analysis of the elastic scattering of nucleons by ⁴He, ¹²C and ¹⁶O targets. A good fit of the experimental phase shifts is obtained with almost the same values of the potential parameters for neutron-nucleus and proton-nucleus elastic scattering.     

On relativistic and non-relativistic approaches to nucleon-nucleus scattering

The impulse approximation to the Dirac theory of nucleon-nucleus scattering is reduced to a non-relativistic formalism. It is shown that relativistic effects can be included on the same footing as the effects of the nuclear medium on the effective interaction. We apply the argument to spin observables in 200 MeV and 500 MeV proton elastic scattering on a ⁴⁰Ca target.     

Relativistic mean field approach to the scattering of antinucleons and nucleons by nuclei

A realistic mean field approach based on the Walecka theory for nuclear matter is used to derive the optical potential for nucleon and antinucleon-nucleus systems. The total and reaction cross sections are calculated in the WKB approximation for different nuclei ranging from carbon to lead and for incident energies between 0.1 and 2 GeV.     

Perturbation approach to time resolved stimulated Brillouin scattering

The laser beam intensity changes, due to time resolved stimulated Brillouin scattering, were studied analytically using perturbation approach. It was shown, that the derived expressions enables a qualitative understanding of the previously reported results of the experimental as well as numeric investigations.     

A nuclear structure approach to the nucleon-nucleus optical potential at low energy

An antisymmetrized microscopic calculation of the optical potential for nucleon-⁴⁰Ca elastic scattering is derived. RPA correlations taken into account in the one-particle mass operator are shown to bring a correction to the first-order real potential at low energies and to lead to an imaginary potential. Both are calculated for incident nucleon energies between 10 and 50 MeV. Their general properties are studied in great detail and, after comparison with empirical imaginary potentials, the reliability of such an approach is discussed according to the value of the incident energy.     

Local and nonlocal space-like fields in the relativistic description of nucleon-nucleus scattering

It is shown that a local complex space-like nucleon-nucleus potential does not influence the observables associated with the elastic scattering, in contrast to a nonlocal space-like potential obtained from nuclear matter via a local density approximation. In order to eliminate the nonlocal space-like field, new scalar and time-like local components are defined. The energy dependence of the ratio of the strengths of the real parts of these two quantities is investigated.     

Relativistic corrections to electron scattering: (II). Inelastic scattering

Relativistic corrections to inelastic electron scattering have been investigated using the results of a previous calculation on elastic scattering. A detailed discussion is made of the kinematics of inelastic scattering. Excitation of discrete states is treated in detail by two different methods, with particular attention paid to kinematical factors. Deuteron breakup is discussed and treated in a very similar manner to the discrete excitations. Comparison is made with analyses using plane wave final states and with previous work.     

Potential scattering in Dirac field theory

We develop the potential scattering of a spinor within the context of perturbation field theory. As an application, we reproduce, up to second order in the potential, the diffusion results for a potential barrier of quantum mechanics. An immediate consequence is a simple generalization to arbitrary potential forms, a feature not possible in quantum mechanics.     

A Dirac algebraic approach to supersymmetry

The power of the Dirac algebra is illustrated through the Kähler correspondence between a pair of Dirac spinors and a 16-component bosonic field. The SO(5, 1) group acts on both the fermion and boson fields, leading to a supersymmetric equation of the Dirac type involving all these fields.     

Some aspects of redundant states in nucleon-nucleus scattering solutions with antisymmetrization

Redundant states are known to appear as solutions to the scattering equation when an incident particle is antisymmetrized with respect to a target nucleus represented by a Slater determinant. Using criteria which have been found to characterize a potential which produces a continuum bound state (CBS), we demonstrate that a redundant solution can be identified as a CBS which appears at every positive energy. This identification provides a procedure for isolating and removing that portion of the potential responsible for redundant states. The remaining portion of the potential generates solutions to the original scattering equation which we demonstrate to be orthogonal to the redundant states which have been eliminated.     

Relativistic corrections to electron scattering by the deuteron and triton

Relativistic corrections to electron-deuteron and electron-³He scattering have been calculated. the deuteron corrections agree substantially with the results of Gross and the ³He corrections are approximately equal in magnitude to those of Cocho and Flores.