Charge-Exchange and multi-scattering effects in (e,e'n) knockout

Final-state interactions in (e,e'n) knockout reactions in the quasi-free region are studied by considering the multistep direct scattering of the ejectile nucleon. Primary and multiple particle emission are included within the same model and are found to become important with increasing excitation energy. Charge-exchange effects taken into account through the two-step (e,e'p)(p,n) and three-step (e,e'p)(p,N)(N,n) processes are also found to increase with energy. A comparison with the results obtained with an isospin-dependent optical potential at small excitation energies is presented.Comment: 12 pages, 4 Postscript figures. A new section on multiple particle emission added together with 2 new figures including primary and multiple emission cross section

Antisymmetrized Green's function approach to (e,e′)(e,e') reactions with a realistic nuclear density

A completely antisymmetrized Green's function approach to the inclusive quasielastic $(e,e')$ scattering, including a realistic one-body density, is presented. The single particle Green's function is expanded in terms of the eigenfunctions of the nonhermitian optical potential. This allows one to treat final state interactions consistently in the inclusive and in the exclusive reactions. Nuclear correlations are included in the one-body density. Numerical results for the response functions of $^{16}$O and $^{40}$Ca are presented and discussed.Comment: 45 pages, 3 figure

Signatures for short-range correlations in {16}O, observed in the reaction {16}O(e,e'pp){14}C.

The reaction O-16(e,e'pp)C-14 has been studied at a transferred four-momentum (omega,\q\) = (210 MeV, 300 MeV/c). The differential cross sections for the transitions to the ground state and the lowest excited states in C-14 were determined as a function of the momentum of the recoiling C-14 nucleus and the angle between the momentum of the proton emitted in the forward direction and the momentum transfer q. A comparison of the data to the results of calculations, performed with a microscopic model, shows clear signatures for short-range correlations in the O-16 ground state

Polarization mesurements in electromagnetic reactions

A review is given of the possible polarization measurements in electromagnetic reactions at intermediate energies

Separation of structure functions and electron distortion in quasifree (e, e′p) reactions

In the one-photon exchange approximation the coincidence cross section of the quasifree (e, e′p) reaction can be written in terms of four structure functions, which represent the response of the nucleus to the various components of the electromagnetic interaction. The role of Coulomb distortion of electrons on the separation of these structure functions is investigated. The distorted-electron wave functions are given by an expansion in powers of Zα, whose validity is discussed. The effect of electron distortion on the separation of longitudinal and transverse responses in parallel kinematics is considered, taking 40Ca and 208Pb as study cases. The effect is found to be significant. However, whereas for 40Ca it can be eliminated, with a good degree of accuracy, by correcting the cross section through effective momentum transfer, in 208Pb also large contributions due to the focusing of the electron wave must be carefully subtracted. The determination of longitudinal-transverse interference structure function in coplanar perpendicular kinematics is also discussed

Complete determination of scattering amplitudes and nucleon polarization in electromagnetic knockout reactions

The electron-induced knockout reactions are investigated aiming at the complete determination of scattering amplitudes. This result can be achieved only by exploiting spin degrees of freedom and therefore through polarization experiments where the components of the nuclear response are separated. Particular situations are envisaged where at least a partial determination can be obtained by measurements compatible with the present experimental facilities. Numerical predictions are presented and discussed for polarization of an outgoing proton or neutron in coplanar kinematics. The role of final-state interactions and of Coulomb distortion of electron waves is investigated. In the case of an outgoing neutron, the two-step charge-exchange contribution, due to an isospin-dependent term in the optical potential, is also included

Electron distortion in quasifree (e,e′p) reactions

Effects of Coulomb distortion of the electron wave functions in the quasifree (e, e′p) reactions are investigated in DWBA. Electron waves are described by a high energy approximation. The coincidence cross section is calculated in a nonrelativistic approach based on the impulse approximation. Results are presented and discussed for different nuclei in different kinematical conditions. Coulomb distortion gives two different effects. The first one is to change the momentum transfer into an effective momentum transfer. This effect is dominant for light nuclei and decreases by increasing incident electron energy. The second one is the focusing of the electron wave in the nuclear Coulomb field. This effect, almost energy independent, is sizeable in medium and heavy nuclei. It increases the cross section and in some cases becomes very large

Electron-Nucleon Interaction in Quasi-Free Scattering. II Non-Relativistic Hamiltonian thorugh Fourth Order

The interaction of non-relativistic nucleons with relativistic electrons can be expressed by a Hamiltonian expanded in a power series of the recoil nucleon velocity. In this paper third- and fourth-order terms are calculated. Free electron-nucleon-scattering and quasi-free electron scattering on 12C are studied and results through various orders are compared with the relativistic formulae. A different off-shell behaviour of the relativistic approach is found, which is independent of the higher-order terms and seems responsible for the different results of knock-out reactions

Coulomb distortion effects and determination of structure functions in quasifree (e,e'p) reactions

The role of Coulomb distortion of the electron waves on the determination of nuclear structure functions in quasifree (e,e'p) reactions is investigated