0000000000230326

AUTHOR

K. M. Schmitt

showing 7 related works from this author

Survey on polarization observables in deuteron photodisintegration below pion-production threshold

1991

Polarization observables of deuteron photodisintegration with polarized photons and oriented deuterons are systematically investigated below π-production threshold with respect to their sensitivity to subnuclear degrees of freedom and relativistic effects, to the different electric and magnetic multipole contributions, and to various realistic potential models. In particular, a complete survey on all single- and double-polarization observables like beam and target asymmetries of the differential cross section, nucleon polarization and proton-neutron spin correlation is given.

PhysicsParticle physicsPhotonNuclear TheoryObservablePolarization (waves)Atomic and Molecular Physics and OpticsNuclear physicsPionPhotodisintegrationNuclear ExperimentNucleonRelativistic quantum chemistryMultipole expansionFew-Body Systems
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Deuteron photodisintegration at low energies

1991

All presently available experimental data on deuteron photodisintegration below 40 MeV (i.e., total and differential cross sections, photon asymmetry and neutron polarization) are collected and carefully compared with the present status of the conventional theory (i.e., in the framework of mesontheoretical or semi-phenomenologicalN-N potentials including subnuclear degrees of freedom and relativistic corrections). No significant evidence for a failure of the conventional theory is found within the present experimental accuracy.

Scattering cross-sectionPhysicsParticle physicsPhotonmedia_common.quotation_subjectNuclear TheoryElementary particlePolarization (waves)AsymmetryAtomic and Molecular Physics and OpticsNuclear physicsDeuteriumPhotodisintegrationNeutronNuclear Experimentmedia_commonFew-Body Systems
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Relations between polarization observables and complete sets for deuteron photodisintegration

1990

The polarization observables for deuteron photodisintegration are given as Hermitean forms of theT-matrix elementsti. By inversion we are able to express a given productti*tj in terms of polarization observables. This allows (i) to derive linear relations between observables for unpolarized, circularly and linearly polarized photons, (ii) to construct explicitly complete sets of polarization observables, and (iii) to derive quadratic relations between observables.

PhysicsNuclear physicsParticle physicsPhotonQuadratic equationDeuteriumLinear polarizationPhotodisintegrationPolarization observablesObservableAtomic and Molecular Physics and OpticsFew-Body Systems
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Meson-retardation effects in deuteron photodisintegration below ?-threshold

1989

Mesor-retardation effects in photodisintegration of the deuteron below pion threshold are studied by constructing retarded one-boson-exchange potentials using time-dependent non-covariant perturbation theory. The corresponding retarded meson-exchange currents including retarded vertex currents are derived analogously by gauge-invariant minimal coupling. It is found that retardation effects in the wave functions and in the electromagnetic currents as well have a significant influence on total and differential cross sections.

Minimal couplingPhysicsMesonNuclear TheoryElementary particlePhysics::Classical PhysicsAtomic and Molecular Physics and OpticsVertex (geometry)Nuclear physicsPionDeuteriumPhotodisintegrationQuantum electrodynamicsNuclear ExperimentWave functionFew-Body Systems
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Deuteron photodisintegration with the Bonn OBE potentials

1989

The various OBE approximations to the recent Bonn potential are studied in deuteron photodisintegration below π-threshold. Consistent static meson-exchange currents, isobar currents, and the relativistic spin-orbit current are included. Concerning the OBEPT also the leading retardation corrections in the currents are taken into account. Comparison with experimental data is carried out in detail.

Nuclear physicsPhysicsParticle physicsDeuteriumPhotodisintegrationNuclear TheoryIsobarNuclear ExperimentAtomic and Molecular Physics and OpticsFew-Body Systems
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Heavy-mesons exchange and the backward deuteron electrodisintegration

1992

Backward electrodisintegration of the deuteron is calculated using an exchange-current operator containing π, η, ρ, ω, δ, σ, andA1 exchanges. The deuteron and1S0np wave functions are derived from the Bonn OBEPs. For completeness, we introduced theA1-meson exchange into the OBEP's as well. As a consequence, the value ofD-state probabilityPD is increased by 0.2%–0.8%. The computed cross sections are compared with new data.

Nuclear physicsParticle scatteringPhysicsParticle physicsMesonDeuteriumOperator (physics)Elementary particleWave functionAtomic and Molecular Physics and OpticsFew-Body Systems
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Integrated photoabsorption strength and sum rules for a bound Dirac particle

1985

Relativistic effects in the integrated total photoabsorption cross section are discussed using a simple model of a Dirac particle bound in a central potential of scalar or vector type. The integrated strength is calculated explicitly and compared to a new relativistic extension of the TRK-sum rule using positive energy projection and to predictions from dispersion relations. M1 and E2 sum rules are also considered. In all cases the integrated strength exceeds the classical sum rule up to a few percent. The dispersion sum rule cannot be compared directly to the integrated strength since it contains a negative contribution from pair production in the potential field which is of the order of a…

PhysicsPositive energyNuclear and High Energy PhysicsPair productionQuantum mechanicsQuantum electrodynamicsDispersion relationScalar (mathematics)Potential fieldNuclear fusionSum rule in quantum mechanicsRelativistic quantum chemistryZeitschrift für Physik A Atoms and Nuclei
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