Polarization structure of reactions atθc.m.=π2

Abstract

The polarization structure of a reaction of particles with arbitrary spins is described at 90° for the case when one or several pairs of identical particles form the reaction. The simplification of the structure is described in the optimal formalism, and particularly in the helicity and transversity frames, and the reduction in the number of independent amplitudes is tabulated for arbitrary spins and for a large assortment of combinations of symmetries. The constraints due to only one pair of identical particles are particularly stressed since these have hardly been utilized in the past. The results are illustrated in elastic proton-proton scattering, and data for this reaction at 800 MeV are analyzed at 90° both phenomenologically and with a specific aim of testing suggestions for the existence of dibaryon resonances. It is shown that at 800 MeV and 90° the proton-proton scattering data are compatible with a resonance of the type that has been suggested, though the data do not demand such a resonance.