Photon absorption on a neutron-proton pair in ${}^3$He

Abstract

The cross section of the reaction ${}^3$He$(\gamma ,pn)p_{spec}$ in the energy range 150 - 450 MeV has been calculated in a quasifree two-body model and compared with a recent kinematically complete experiment. In comparison with free deuteron disintegration the cross section is increased by a factor of about 1.5 in reasonable agreement with the data for photon energies above 200 MeV. At lower energies the data deviate from the two-body behaviour and thus suggest a more important role of the spectator requiring a more exact treatment.

Comments: 7 pages (latex) and 2 figures (postscript) available on request, MKPH-T-94-9