Deuteron photofission in the range Eγ ≤ 1 GeV
Description
The differential cross section and polarisation observables of the deuteron photodisintegration are calculated in a relativistic quantum hadron dynamical model at photon lab. energies Eγ up to 1 GeV. We have used the method of Feynmangraphs to calculate the T-Matrix of the process γ d → p n. A central point is the consideration of boxgraphs with baryon-resonances with spin ≤ 3/2 and masses < 2 GeV. The exchange of π-, ω-, ρ- and η-mesons is used to approximate the final state interaction. The analytical structure of the elementary amplitudes of these boxgraphs is investigated with respect to their offshell behaviour. Moreover, the influence of the deuteron wavefunction, including P-waves, and the meson formfactors are major points under consideration. It is shown that the 'spectator model pole' yields the most significant contribution to the amplitude of the planar boxgraphs. For the nonplanar graph of the MEC, which is required to restore gauge invariance, the spectatormodel leads to unphysical singularities. (orig.)
Availability note (English)
MF available from INIS under the Report Number.Abstract (German)
Wir haben in dieser Arbeit die Deuteron-Photospaltung im Rahmen der QHD behandelt. Zur Berechnung der T-Matrix wurde die Methode der Feynmangraphen verwendet. Von entscheidender Bedeutung war dabei die Berechnung von Boxgraphen. In diesen Boxgraphen wurden die Spin 1/2 und Spin 3/2 Baryonresonanzen mit einer Masse < 2 GeV, sowie der Austausch von π-, ω-, ρ- und η-Mesonen beruecksichtigt. Unser besonderes Interesse galt der Untersuchung von off-shell Effekten in den Boxgraphen, vor allem in Zusammenhang mit der Deuteron-Vertexfunktion. Wir haben gesehen, dass fuer die s-Kanal Graphen strukturloser Teilchen die On-Shell Approximation (OSA) eine durchaus gute Naeherung darstellt. Die off-shell Eigenschaften der Deuteron Vertexfunktion sowie die Einfuehrung von verallgemeinerten Formfaktoren bewirken jedoch merkliche Differenzen zwischen der OSA und der 'exakten' Rechnung. Dies ist leicht einzusehen, da hierdurch die analytische Struktur der Amplituden (z.B. Lage und Anzahl der Pole) veraendert wird. Desweiteren fanden wir, dass u-Kanal Graphen (Mesonbox) aufgrund der analytischen Struktur ihrer Amplituden im Rahmen der OSA nicht befriedigend wiedergegeben werden koennen. (orig.)
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Additional details
Additional titles
- Original title (German)
- Deuteronphotospaltung im Bereich E
Publishing Information
- Imprint Pagination
- 159 p.
- Report number
- BONN-IR--91-71
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 24017359
- Subject category
- S73: NUCLEAR PHYSICS AND RADIATION PHYSICS; S73: NUCLEAR PHYSICS AND RADIATION PHYSICS;
- Resource subtype / Literary indicator
- Numerical Data, Thesis
- Descriptors DEI
- ANGULAR DISTRIBUTION; BREAKUP REACTIONS; DEUTERIUM TARGET; DIFFERENTIAL CROSS SECTIONS; ENERGY DEPENDENCE; EXCITATION FUNCTIONS; FEYNMAN DIAGRAM; FINAL-STATE INTERACTIONS; FORM FACTORS; GAUGE INVARIANCE; HELICITY; MEV RANGE 100-1000; N*BARYONS; OPE MODEL; P WAVES; PHOTONEUTRONS; PHOTONUCLEAR REACTIONS; PHOTOPROTONS; POLARIZATION-ASYMMETRY RATIO; POLARIZED BEAMS; POLARIZED PRODUCTS; POLARIZED TARGETS; QUANTUM FIELD THEORY; RELATIVISTIC RANGE; S MATRIX; SCATTERING AMPLITUDES; SINGULARITY; SPIN ORIENTATION; THEORETICAL DATA; WAVE FUNCTIONS
- Descriptors DEC
- AMPLITUDES; BARYONS; BEAMS; BOSON-EXCHANGE MODELS; CATIONS; CHARGED PARTICLES; CROSS SECTIONS; DATA; DIAGRAMS; DISTRIBUTION; ELEMENTARY PARTICLES; ENERGY RANGE; FERMIONS; FIELD THEORIES; FUNCTIONS; HADRONS; HYDROGEN IONS; HYDROGEN IONS 1 PLUS; INFORMATION; INTERACTIONS; INVARIANCE PRINCIPLES; IONS; MATHEMATICAL MODELS; MATRICES; MEV RANGE; NEUTRONS; NUCLEAR REACTIONS; NUCLEONS; NUMERICAL DATA; OBE MODEL; ORIENTATION; PARTIAL WAVES; PARTICLE MODELS; PARTICLE PROPERTIES; PERIPHERAL MODELS; PHOTONUCLEONS; PROTONS; TARGETS