Hard Photodisintegration of a Proton Pair in 3He

Abstract

Hard photodisintegration of the deuteron has been extensively studied in order to understand the dynamics of the transition from hadronic to quark-gluon descriptions of the strong interaction. In this work, we discuss the extension of this program to hard photodisintegration of a $pp$ pair in the $^3$He nucleus. Experimental confirmation of new features predicted here for the suggested reaction would advance our understanding of hard nuclear reactions. A main prediction, in contrast with low-energy observations, is that the $pp$ breakup cross section is not much smaller than the one for $pn$ break up.In some models, the energy-dependent oscillations observed for $pp$ scattering are predicted to appear in the $\gamma ^3{\rm He} \to p p + n$ reaction. Such an observation would open up a completely new field in studies of color coherence phenomena in hard nuclear reactions. We also demonstrate that, in addition to the energy dependence, the measurement of the light-cone momentum distribution of the recoil neutron provides an independent test of the underlying dynamics of hard disintegration.