Cross sections for three-body photodisintegration of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ are calculated in the electric dipole approximation. The calculation is performed within the context of exact three-body theory with the two-nucleon interactions represented by $s$-wave spin-dependent separable potentials fitted to low-energy nucleon-nucleon scattering data. The photodisintegration amplitude is expressed in terms of the fully off-shell nucleon-plus-correlated-pair amplitudes, a method applicable to any weak-process disintegration amplitude. The numerical results indicate: (1) The ${}_{}{}^3{}_{}{}^{}\mathrm{He}(\gamma ,n)2p$ total cross section has a peak value of approximately 1 mb. (2) The neutron spectra for ${}_{}{}^3{}_{}{}^{}\mathrm{He}(\gamma ,n)2p$ and the proton spectra for ${}_{}{}^3{}_{}{}^{}\mathrm{He}(\gamma ,p)np$ peak sharply in the region of the strong $p-p$ final-state interaction.

NUCLEAR REACTIONS Photodisintegration of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$; exact three-body calculation; separable potentials; neutron and proton spectra.

• Received 29 September 1975

DOI:https://doi.org/10.1103/PhysRevC.13.477