Neutron spectra from 647- and 800-MeV proton bombardment of hydrogen and deuterium. [Cross sections

Abstract

Zero degree neutron spectra for the inclusive reactions p(p,n) and d(p,n) were obtained. Spectra were obtained for bombarding proton kinetic energies of 647 and 800 MeV. The strongly peaked p(p,n) spectra are well explained via the p(p,n)p..pi../sup +/ reaction primarily through the production of the N*/sub 33/(..delta../sup + +/) resonance. However, there is evidence for n-p final state interactions as well. Calculations have shown the roles of the N*/sub 33/ resonance and the n-p final state interactions in these p(p,n) spectra. The d(p,n) spectra exhibit a strong quasi-elastic charge exchange peak influenced by the final state p-p interaction in the reaction d(p,n)2p. The d(p,n) spectra also show a broad bump at lower neutron momenta qualitatively similar to the p(p,n) spectra. The d(p,n) spectra at lower momenta are nearly explained by nucleon-nucleon single pion production via the N*/sub 33/ resonance but it appears that higher order contributions involving nucleon--nucleon and nucleon--pion interactions are required as well. The d(p,n)2p reaction provides an intense, nearly monoenergetic neutron beam for use as a probe, primarily of the n-p interaction, at medium energies. The d(p,n) and p(p,n) measurements provide zero degree neutron momentum distributions which are very useful in furthering the knowledge about pion productionmore » near the N*/sub 33/ resonance. These data provide a challenge to the theoreticians to explain pion production in the two and three nucleon initial states. (auth)« less