Correlation measurements of the proton spectra in the backward hemisphere in the reaction pd. -->. ppn at 1. 2--1. 7 GeV/c

The reaction pd..-->..ppn with emission of one of the nucleons into the backward hemisphere has been studied in a deuterium bubble chamber at eight energies. In contrast to high energies, an energy dependence of the slope of the invariant cross section is observed, which may indicate a dying out of the isobaric mechanism which may be responsible for a constant contribution in the region above 1 GeV. On the other hand, at large backward angles this mechanism remains important also in the region studied. Investigation of angular correlations and momentum spectra made it possible to identify the regions of dominance of the various diagrams. In the spectrum of the effective masses M/sub p/n a peak is observed which can be interpreted as a candidate for a dibaryon resonance.