H2(p,2p)n at 508 MeV: Recoil momenta≤200MeV/c

Differential cross sections for the reaction ${}_{}{}^2{}_{}{}^{}(\mathit{p}$,2p)n at $T_p$=507 and 508 MeV are presented. The kinematics selected included two quasi-free angle pairs: 41.5°-41.4° and 30.1°-53.75°; in addition, data away from the quasi-free condition were obtained in four symmetric angle pairs: 38.1°-38.0°, 44.1°-44.0°, 47.1°-47.0°, and 50.0°-50.0°, and five asymmetric angles pairs: 30.1°-37.0°, 30.1°-44.0°, 30.1°-61.0°, 30.1°-68.0°, and 41.5°-50.0°. The data range over an energy window 100 MeV wide on one of the proton energies, the second energy being defined by the kinematic condition of a single neutron recoiling. The data are compared with the impulse approximation prediction and with the results of a nonrelativistic calculation of the six lowest-order Feynman diagrams describing the reaction. A previously known missing strength for the reaction in the small neutron recoil region is confirmed with much smaller experimental uncertainty; the missing strength persists up to 150 MeV/c neutron recoil. The onset of a systematic cross section excess relative to the impulse approximation near neutron recoil momentum 200 MeV/c is explored in detail.