Electron Coulomb effects in quasielastic (e,e'p) reactions

• Published in: Physical review. C, Nuclear physics Nuclear physics, 1992-03, Vol.45 (3), p.1311-1320
• Main Authors: Jin, Y, Onley, DS, Wright, LE
• Format: Article
• Language: English
• Subjects: 663420 - Lepton-Induced Reactions & Scattering- (1992-); 663540 - Nuclear Mass Ranges- A=39-58- (1992-); BARYONS; BORN APPROXIMATION; CALCIUM 40 REACTIONS; CHARGED-PARTICLE REACTIONS; CORRECTIONS; COULOMB CORRECTION; CROSS SECTIONS; DIFFERENTIAL CROSS SECTIONS; DIFFERENTIAL EQUATIONS; DIRAC EQUATION; DIRECT REACTIONS; DWBA; ELECTRON REACTIONS; ELEMENTARY PARTICLES; ENERGY RANGE; EQUATIONS; FERMIONS; HADRONS; HEAVY ION REACTIONS; KNOCK-OUT REACTIONS; LEPTON REACTIONS; NUCLEAR PHYSICS AND RADIATION PHYSICS; NUCLEAR REACTIONS; NUCLEONS; OPE POTENTIAL; OPTICAL MODELS; PARTIAL DIFFERENTIAL EQUATIONS; POTENTIALS; PROTONS; QUASI-ELASTIC SCATTERING; QUASI-FREE REACTIONS; RELATIVISTIC RANGE; SCATTERING; WAVE EQUATIONS
• ISSN: 0556-2813; 1089-490X
• DOI: 10.1103/PhysRevC.45.1311

We describe a calculation for the electron Coulomb distortion effects in ({ital e},{ital e}{prime}{ital p}) in the quasielastic region from medium and heavy nuclei. The bound nucleons are described by single-particle Dirac wave functions in the presence of scalar and vector potentials which are parametrized fits to relativistic Hartree potentials, while the wave function of the knocked-out nucleon is a solution to the Dirac equation with the relativistic optical potential. The electron wave functions are solutions to the Dirac equation in the presence of the Coulomb potential of the nucleus and the interaction with the selected nucleon is treated to first order. We examine the {sup 40}Ca({ital e},{ital e}{prime}{ital p}) reaction in both parallel and {omega}-{ital q} constant kinematics. We find that electron Coulomb distortion has a smaller effect in {omega}-{ital q} constant kinematics than in parallel kinematics. The principal effect in parallel kinematics is to shift the maximum and minimum of the reduced cross section which is consistent with the experimental data. Occupation numbers of about 70% to 80% are needed to normalize the distorted-wave Born approximation calculation to the {sup 40}Ca({ital e},{ital e}{prime}{ital p}) experimental data. We also calculate the reduced cross section for the 3{ital s}{sub 1/2} state in {sup 208}Pb and compare our results to experimental data and previous calculations. We find no significant difference in using relativistic, as compared with nonrelativistic, nuclear wave functions. We do find significant corrections to earlier methods of treating Coulomb distortion which, in turn, affect the occupation number extracted from experiment. We find an occupation number for this state of 71.4%.