511 research outputs found
Hadron Structure Studied with the Electromagnetic Probe - from Giant Resonances to Meson Production
The development of theoretical photonuclear physics over the last 40 years is
illustrated by a few selected examples highlighting a number of important
issues like collective motion in nuclei, the role of subnuclear degrees of
freedom, relativity and meson production.Comment: 10 pages latex including 10 figures, invited talk presented at the
Symposium on Fundamental Issues in Elementary Matter, Sept. 25-29, 2000, Bad
Honnef, German
Construction of Consistent Meson Exchange Currents by Laplace Transform
We propose a new method for the construction of a consistent meson exchange
current in -space for the spin-isospin dependent central and tensor part of
phenomenological nucleon-nucleon potentials by using a Laplace transformation,
which allows the representation by a finite number of Yukawa functions. This
method is applied to the Paris and the recent Argonne potentials.
Results are presented for electrodisintegration of the deuteron near threshold.Comment: 13 pages Revtex including 9 figures, final version accepted for
publication in EPJA (one figure and discussion added
The two-nucleon system in the region including full meson retardation
A model is developed for the hadronic and electromagnetic interaction in the
two-nucleon system above pion threshold in the framework of meson, nucleon and
degrees of freedom. It is based on time-ordered perturbation theory
and includes full meson retardation in potentials and exchange currents as well
as loop contributions to the nucleonic one-body current. Results for
scattering and deuteron photodisintegration are presented.Comment: 4 pages Revtex including 2 figures, contribution to "Mesons and Light
Nuclei 2001", Prague, July 2-6, 200
Polarization observables in elastic electron deuteron scattering including parity and time reversal violating contributions
The general formalism for polarization observables in elastic electron
deuteron scattering is extended to incorporate parity and time reversal
violating contributions. Parity violating effects arise from the interference
of and exchange as well as from the hadronic sector via a small
parity violating component in the deuteron. In addition we have allowed for
time reversal invariance violating contributions in the hadronic sector. Formal
expressions for the additional structure functions are derived, and their
decomposition into the various multipole contributions are given explicitly.Comment: 34 pages Revte
Photonuclear effect in heavy deformed nuclei
The theory of Raman scattering is extended to include electric-quadrupole radiation. The results obtained are used to compute the elastic and Raman scattering cross sections of heavy deformed nuclei. The dipole and quadrupole resonances are described by a previously developed theory which includes surface vibrations and rotations. The computed cross sections are compared with experimental data for all those nuclei where both absorption and scattering cross sections are available. Some discrepances still exist in certain details; however, the over-all agreement between theory and experiment is very good
Complete Sets of Polarization Observables in Electromagnetic Deuteron Break-up
For deuteron photo- and electrodisintegration the selection of complete sets
of polarization observables is discussed in detail by applying a recently
developed new criterion for the check of completeness of a chosen set of
observables. The question of ambiguities and their resolution by considering
additional observables is discussed for a numerical example, for which the role
of experimental uncertainties is also investigated. Furthermore, by inversion
of the expressions of the observables as hermitean forms in the -matrix
elements a bilinear term of the form can be given as a complex
linear form in the observables from which an explicit solution for in
terms of observables can be obtained. These can also be used to select sets of
observables for the explicit representation of the -matrix.Comment: 37 pages revte
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