J. Heisenberg

Nuclear Transition Density Determinations from Inelastic Electron Scattering

The determination of nuclear charge distributions through elastic electron scattering is well known and has been the subject of several articles and review articles. (See Refs. 1–3, etc.) Inelastic electron scattering by its nature is very similar: It allows the determination of some dynamical properties of the nucleus. These are the transition charge or current densities which represent the changes in the charges or the currents associated with the transition of the nucleus from the initial state to the final state. These transition charge or current densities are the same as those that cause the y transitions between these states or that allow the nucleus to be excited by the Coulomb field of a passing heavy ion. Thus electron scattering is not an isolated field, rather it provides additional information on these densities which, combined with the results from other electromagnetic probes, can be used for a more complete determination of the transition properties.

Ground state correlations and mean field in {sup 16}O

We use the coupled cluster expansion [exp(S) method] to generate the complete ground state correlations due to the NN interaction. Part of this procedure is the calculation of the two-body {bold G} matrix inside the nucleus in which it is being used. This formalism is being applied to {sup 16}O in a configuration space of 50{h_bar}{omega}. The resulting ground state wave function is used to calculate the binding energy and one- and two-body densities for the ground state of {sup 16}O. {copyright} {ital 1999} {ital The American Physical Society}

Coulomb distortion effects in deep-inelastic electron scattering

Abstract The effects of the Coulomb distortion of the electron wave functions in the description of the electron scattering processes in the quasi-elastic region are discussed. A method to extract longitudinal and transverse response functions considering these effects is presented. While the transverse response function is remarkably affected by the Coulomb distortion, the values of the longitudinal response function are practically unchanged.

Center-of-mass corrections reexamined: A many-body expansion approach

A many-body expansion for the computation of the charge form factor in the center-of-mass system is proposed. For convergence testing purposes, we apply our formalism to the case of the harmonic oscillator shell model, where an exact solution exists. We also work out the details of the calculation involving realistic nuclear wave functions. Results obtained for the Argonne

Electro-excitation of the 1+ state at Ex = 3.486 MeV in 88Sr

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Measurement of the effective E5 single-particle transition densities in 89Y and 90Zr

18 two-nucleon and Urbana-IX three-nucleon interactions are reported. No corrections due to the meson-exchange charge density are taken into account.

High multipolarity electroexcitations in 207Pb and 206Pb

Abstract The differential cross section for excitation of the 1 + state at E x = 3.486 MeV in 88 Sr by inelastic electron scattering has been measured for values of the momentum transfer f between 0.22 and 2.57 fm −1 . Both nuclear core polarization and Δ -hole polarization seem to be necessary to describe the observed reduction of the B (M1) value and data at low q and the behaviour of the cross section at intermediate values of q .

The effects of triaxial deformations in the structure of the 2(1)+ transition charge density in 58Ni

The transition charge and current densities for the lowest E5 proton particle-hole excitation in 89Y (0.909 MeV) and 90Zr (2.319 MeV) have been extracted from electron scattering data. These excitations are dominated by the π(1 g92, 2 p−192) configuration. The transition densities indicate the importance of configuration mixing in the ground state of 90Zr. Single-particle predictions do not reproduce the shape of the empirical densities indicating the need for a surface peaked core polarization correction in both the charge and current densities.

Transition charge densities for the lowest E5 transitions in 208Pb

Abstract We report the identification of new high multipolarity transitions in 207 Pb and 206 Pb by the measurement of their form factor. A comparison to the corresponding excitations in 208 Pb is presented.

High resolution elastic and inelastic scattering

Abstract Inelastic electron scattering cross sections have been measured up to a momentum transfer q =3.9 fm −1 , determining very precisely the transition charge density of the first excited 2 (1) + state of 58 Ni. The results have been interpreted in a fully self-consistent theoretical treatment for both the ground state and the 2 (1) + transition charge density of 58 Ni. The model applied is a collective description where the dynamics of the motion induces a non-zero deformation with nearly maximum triaxiality ( γ =30°). It is found that an adjustment of the collective wave function is needed to reproduce the measured transition charge density.