[show abstract][hide abstract] ABSTRACT: We have measured cross sections for the gamma+3He->p+d reaction at photon
energies of 0.4 - 1.4 GeV and a center-of-mass angle of 90 deg. We observe
dimensional scaling above 0.7 GeV at this center-of-mass angle. This is the
first observation of dimensional scaling in the photodisintegration of a
nucleus heavier than the deuteron.
[show abstract][hide abstract] ABSTRACT: We present a study of high energy photodisintegration of proton-pairs through the channel. Photon energies, Eγ, from 0.8 to 4.7 GeV were used in kinematics corresponding to a proton pair with high relative momentum and a neutron nearly at rest. The s−11 scaling of the cross section, as predicted by the constituent counting rule for two nucleon photodisintegration, was observed for the first time. The onset of the scaling is at a higher energy and the cross section is significantly lower than for deuteron (pn pair) photodisintegration. For Eγ below the scaling region, the scaled cross section was found to present a strong energy-dependent structure not observed in deuteron photodisintegration.