Exact Distorted-wave Born Approximation Research Articles

Exact and approximate postform distorted-wave Born approximation amplitudes for the Coulomb breakup of neutron halo nuclei

The Coulomb breakup of neutron halo nuclei is considered within the framework of the postform distorted-wave Born approximation (DWBA). The quality of commonly used additional approximations to the DWBA theory is investigated by comparing the approximate with the exact DWBA calculations. The exact DWBA amplitude is expressed in momentum space as a three-dimensional integral and evaluated numerically. Calculations are presented for the Coulomb breakup of deuteron and ${}^{11}\mathrm{Be}$ at very forward angles at the beam energy of $\ensuremath{\sim}70 \mathrm{MeV}/\mathrm{nucleon}.$ The factorization approximation to the DWBA amplitude is studied and found to be suspected.

Approximate Coulomb distortion effects in (e,e′p) reactions

In this paper we apply a well-tested approximation of electron Coulomb distortion effects to the exclusive reaction (e,e{sup {prime}}p) in the quasielastic region. We compare the approximate treatment of Coulomb distortion effects to the exact distorted wave Born approximation evaluated by means of partial wave analysis to gauge the quality of our approximate treatment. We show that the approximate Mo/ller potential has a plane-wave-like structure and hence permits the separation of the cross section into five terms which depend on bilinear products of transforms of the transition four current elements. These transforms reduce to Fourier transforms when Coulomb distortion is not present, but become modified with the inclusion of Coulomb distortion. We investigate the application of the approximate formalism to a model of {sup 208}Pb(e,e{sup {prime}}p) using Dirac-Hartree single particle wave functions for the ground state and relativistic optical model wave functions for the continuum proton. We show that it is still possible to extract, albeit with some approximation, the various structure functions from the experimentally measured data even for heavy nuclei. {copyright} {ital 1997} {ital The American Physical Society}