HYPOTHESIS OF M1 DOMINANCE IN 3/2+-ISOBAR PRODUCTION REACTIONS

The hypothesis that the N and A2N vertices are predominantly of the magnetic-dipole (M1) type is investigated in detail with reference to the 32+-isobar production reactions at high energies. The incorporation of this hypothesis for the Regge exchanges of and A2 mesons is greatly facilitated by our choice of Reggeizing the invariant amplitudes, a choice which avoids spurious parametrizations of the unknown Regge residues and which automatically satisfies all the constraint conditions at the normal thresholds and pseudothresholds. The simple model which assumes only M1 couplings and SU(3) symmetry at the Regge vertices is in satisfactory agreement with the available high-energy data on the differential cross sections and density matrix elements of the reactions +p0()++, -p-+, and K+pK0++. The presence of a small E2 coupling at the vector-meson vertex, in addition to the dominant M1 coupling, is shown to provide an improved fit with experiment near the forward direction. © 1969 The American Physical Society.