A consistent calculation of dispersion corrections in elastic electron-deuteron scattering
T. Herrmann1,2 - R. Rosenfelder2
1 Fakultät f. Physik, Universität Kaiserslautern, D-67663 Kaiserslautern,
Germany
2 Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
Received: 2 December 1997 Communicated by F. Lenz
Abstract
We calculate the contribution of virtual second-order excitations of the deuteron
by integrating numerically over a generalized inelastic structure function 
. This structure function, as well as the ground state density, are
evaluated analytically using the separable Yamaguchi S-wave NN-potential which gives a
fair description of low-energy deuteron properties and nuclear polarization shifts. In the
static case excellent numerical agreement is found by comparing the second-order Born
results with a partial-wave calculation. In the non-static case recoil corrections are
also taken into account but only Coulomb excitations, which should be dominant for small
momentum transfers, are retained. In contrast to previous calculations the present
approach avoids uncontrolled approximations like the closure approximation or mixing of
different models for ground and excited states. We show that the closure approximation with
a fixed average excitation energy is unable to reproduce our numerical results which are
found to be smaller than in previous estimates, negative and dependent both on scattering
angle and incident electron energy. An analysis of experimental scattering cross sections
at low momentum transfer is performed including static Coulomb and dispersion corrections.
In agreement with a recent analysis it is found that the Coulomb corrections increase
the charge radius by 0.012 fm whereas our dispersion corrections lead to a decrease of only
0.003 fm. This gives a deuteron radius of 
fm and a charge radius of
fm.
PACS
25.30.Bf Elastic electron scattering -
21.10.Ft Charge distribution -
21.45.+v Few-body systems
Copyright Springer-Verlag
