292 research outputs found
General Survey of Polarization Observables in Deuteron Electrodisintegration
Polarization observables in inclusive and exclusive electrodisintegration of
the deuteron using a polarized beam and an oriented target are systematically
surveyed using the standard nonrelativistic framework of nuclear theory but
with leading order relativistic contributions included. The structure functions
and the asymmetries corresponding to the various nucleon polarization
components are studied in a variety of kinematic regions with respect to their
sensitivity to realistic -potential models, to subnuclear degrees of
freedom in terms of meson exchange currents, isobar configurations and to
relativistic effects in different kinematical regions, serving as a benchmark
for a test of present standard nuclear theory with effective degrees of
freedom.Comment: 56 pages, 32 figures, revtex
Spin asymmetry and GDH sum rule for real and virtual photons for the deuteron
An explicit evaluation of the spin asymmetry of the deuteron and the
associated GDH sum rule is presented which includes disintegration, single and
double pion and eta production. For the GDH integral a large cancellation is
found between the disintegration channel and the meson production channels.
Furthermore, first results for the contribution of the disintegration channel
to the generalized GDH integral at constant four-momentum transfer reveal a
dominance of the isovector M1 transition to the S-state near threshold
resulting in a negative contribution with a minimum around
fm which is driven by the nucleon anomalous isovector magnetic moment.Comment: 9 pages, 7 figures, World Scientific style, invited talk at GDH 2004
Symposiu
On the Gerasimov-Drell-Hearn sum rule for the deuteron
The Gerasimov-Drell-Hearn sum rule is evaluated for the deuteron by explicit
integration up to 550 MeV including contributions from the photodisintegration
channel and from coherent and incoherent single pion production as well. The
photodisintegration channel converges fast enough in this energy range and
gives a large negative contribution, essentially from the resonant
state near threshold. Its absolute value is about the same size as the sum of
proton and neutron GDH values. It is only partially cancelled by the single
pion production contribution. But the incoherent channel has not reached
convergence at 550 MeV.Comment: 6 pages latex including 3 postscript figures, talk at the 15th Int.
Conf. on Few-Body Problems in Physics, Groningen, Netherlands, 22-26 July
1997. To be published in Nucl. Phys.
Explicit pionic degrees of freedom in deuteron photodisintegration in the Delta-resonance region
Photodisintegration of the deuteron above pi-threshold is studied in a
coupled channel approach including N-Delta- and pi-d-channels with pion
retardation in potentials and exchange currents.Comment: 5 pages latex including 6 postscript figures, talk at the 15th Int.
Conf. on Few-Body Problems in Physics, Groningen, Netherlands, 22-26 July
1997. To be published in Nucl. Phys.
Incoherent single pion electroproduction on the deuteron with polarization effects
Incoherent pion electroproduction on the deuteron is studied from threshold
up to the second resonance region with special emphasis on the influence of
final state interaction, in particular on polarization observables. The
elementary amplitude is taken from the MAID-2003 model.
Final state interaction is included by considering complete rescattering in the
final and subsystems. Their influence on the structure functions
governing the semi-exclusive differential cross section, where besides the
scattered electron only the produced pion is detected, is investigated in
detail. For charged pion-production the effect of -rescattering is moderate
whereas -rescattering is almost negligible, except very close to
threshold. -rescattering appears much stronger in neutral pion production
for which the primary mechanism is the elimination of a significant spurious
coherent contribution in the impulse approximation. Sizeable effects are also
found in some of the polarization structure functions for beam and/or target
polarizations.Comment: 20 pages including 14 figure
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