Photoreactions above the giant dipole resonance

Giannini, M.; Ricco, G.

doi:10.1007/bf02724342

Cited by 20 publications

(11 citation statements)

References 213 publications

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“…However, the calculations do have some differences. Foremost among these is the description used for the electric transition operator, defined [29] for a photon with moment, um q and polarization A as V x (jl.(qr)YII. i, (r)) .…”

Section: Differences In Bpa Calculationsmentioning

confidence: 99%

Ca40photoneutron cross section above the giant dipole resonance

et al. 1991

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The Ca(p, n) reaction cross section has been measured with tagged photons with energies ranging from 31.2 to 102 MeV, for neutron emission angles of 45', 60', 75', 90', and 135'. Exclusive difFerential cross sections for the Ca(p, n) andCa(p, p) reactions are found to be of a similar magnitude, but are not well predicted by recent random-phase-approximation and relativistic direct knock-out calculations. A quasideuteron model calculation with spin-orbit splitting of single-particle shells and an improved nucleon transparency correction is found to be consistent with the data. However, it is shown that this does not establish that the photoabsorption matrix element for the deuteron is necessarily similar to that of a correlated np-pair in nuclear matter. This result is generalized to question the predicted sensitivity to short-range correlations for photonuclear reactions calculated within the Gottfried factorization.

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Section: Differences In Bpa Calculationsmentioning

confidence: 99%

Ca40photoneutron cross section above the giant dipole resonance

et al. 1991

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“…(6.9), namely κ = 0.35 ± 0.10 (see, e.g., Ref. [91]). For the OBEPR(B) version of the Bonn potential the difference would be even bigger since then κ is predicted to be equal to κ = 0.50.…”

Section: B Two-body Seagull Amplitude: Low-energy Behaviormentioning

confidence: 96%

Deuteron Compton scattering below pion photoproduction threshold

2000

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Deuteron Compton scattering below pion photoproduction threshold is considered in the framework of the nonrelativistic diagrammatic approach with the Bonn OBE potential. A complete gauge-invariant set of diagrams is taken into account which includes resonance diagrams without and with NN-rescattering and diagrams with one- and two-body seagulls. The seagull operators are analyzed in detail, and their relations with free- and bound-nucleon polarizabilities is discussed. It is found that both dipole and higher-order polarizabilities of the nucleon are needed for a quantitative description of recent experimental data. An estimate of the isospin-averaged dipole electromagnetic polarizabilities of the nucleon and the polarizabilities of the neutron is obtained from the data.Comment: 48 pages, 16 figures, final version; discussion is slightly extended, a few references added, a figure for asymmetry is replace

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“…(11), usually neglected in the study of photo-nuclear reactions [24,25,49,52]. The ratios between the transverse responses, Eq.…”

Section: The Electromagnetic Currentsmentioning

confidence: 99%

“…Detailed derivations of these expressions can be found in review articles [24] and books [25,26]. We work in natural units (h -= c = 1, e 2 = 1/137.04) and employ the conventions of Bjorken and Drell [27].…”

Section: The Cross Sectionsmentioning

confidence: 99%

Short-Range Correlations and Meson Exchange Currents in Photonucleon Emission

et al. 2002

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One-nucleon emission processes induced by photon absorption are studied by considering shortrange correlation effects. At energies above the giant resonance region the validity of the direct knockout model has been tested by comparison with continuum random phase approximation results. Nucleon re-scattering effects have been considered by using an optical potential. The role of the electromagnetic convection, magnetization, and meson exchange currents has been investigated as a function of both excitation energy and momentum transfer. The short-range correlation effects have been studied by using various correlation functions. We found that the nucleon photo-emission cross section is rather sensitive to the presence of short-range correlations at large values of nucleon emission angle. In this region, however, the effects of meson exchange currents are even larger than those produced by short-range correlations. C 2002 Elsevier Science (USA)

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Photoreactions above the giant dipole resonance

Cited by 20 publications

References 213 publications

Ca40photoneutron cross section above the giant dipole resonance

Ca40photoneutron cross section above the giant dipole resonance

Deuteron Compton scattering below pion photoproduction threshold

Short-Range Correlations and Meson Exchange Currents in Photonucleon Emission

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