Partial-wave analysis of K+p elastic scattering

We have analyzed K+p cross-section and polarization data in the momentum range 0.78–2.53 GeV/c. Single energy fits were made using an ACE parametrization which had no cutoff in J, was analytic and had Regge-asymptotic behavior in the cut cos θ plane, and contained explicit contributions from P, ϱ, A2, Λ, Σ, and low-mass di-pion exchange. Direct channel analyticity constraints were imposed by a partial-wave dispersion relation interpolation procedure, fitting expansions in regulated-norm optimal bases to each partial wave which entered as a search parameter in the single energy fits. Output from these two programs was then used for a simultaneous fit by a linearized least squares program which provided input for another iterative fitting cycle. We find no strong evidence for the existence of exotic resonances. The method of analytic smoothing, in comparison with “shortest path” methods, is found to allow more significant threshold structure to appear in the amplitudes.