Multinucleon Mechanisms in ($\gamma$,N) and ($\gamma$,NN) Reactions

Abstract

The similarities in the experimental indications for multinucleon mechanisms in $(\gamma ,p)$ and $(e,e^{\prime }p)$ processes are pointed out. For both types of reactions, the substantial role of two-nucleon emission processes for transitions to high excitation energies in the residual nucleus is stressed. A microscopic model for the calculation of the two-body knockout contributions to the inclusive $(\gamma ,N)$ reaction is presented. It is based on an unfactorized formalism for the calculation of electromagnetically induced two-nucleon emission cross sections. The model is shown to yield a reasonable description of the overall behaviour of the ${}^{12}$C$(\gamma ,p)$ and ${}^{12}$C$(\gamma ,n)$ data at high excitation energies in the residual nucleus. In the calculations effects from non-resonant and resonant pion exchange currents are included. Photoabsorption on these currents are predicted to produce the major contributions to the exclusive ${}^{16}$O$(\gamma ,n_0{)}^{15}$O process at photonenergies above the pion threshold. Double differential cross sections for photon induced $pp$ and $pn$ emission from ${}^{16}$O are calculated and compared with the data.

18 pages, Revtex 3.0, 13 figures (available upon request), SSF93-10-01

References in corpus (4)

• The Single-Particle Spectral Function of ${}^{16}\mathrm{O}$
• Effects of the final-state interaction in ($\gamma$,pn) and ($\gamma$,pp) processes
• Effects of meson-exchange currents on the $(\protect\vec{e},e'p)$ structure functions
• Simultaneous Microscopic Description of 16O(gamma,n) and 16O(gamma,p) Including Delta Degrees of Freedom

Cited by in corpus (19)

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• Photon-induced two-nucleon knockout reactions to discrete final states
• Treatment of the $\Delta$ current in electromagnetic two-nucleon knockout reactions
• Meson exchange currents in a relativistic model for electromagnetic one nucleon emission
• Two-nucleon knockout contributions to the ${}^{12}$C$(e,e^{\prime }p)$ reaction in the dip and {$\Delta$}(1232) regions
• Quasielastic 12C(e,e'p) Reaction at High Momentum Transfer
• Photo-emission of two protons from nuclei
• Damping mechanisms of the Delta resonance in nuclei
• A Measurement of the Interference Structure Function, R_LT, for the 12C(e,e'p) reaction in the Quasielastic Region
• Short-range correlations and meson exchange currents in photonucleon emission
• Nucleon-Nucleon Correlations and Two-Nucleon Currents in Exclusive ($e,e^{\prime }NN$) Reactions
• Two-proton overlap functions in the Jastrow correlation method and cross section of the ${}^{16}$O$(e,e^{\prime }pp{)}^{14}$C${}_{g.s.}$ reaction
• Relationships between two--particle overlap functions and the two--body density matrix for many-fermion systems