Partial-wave analysis of theK¯Nsystem from 360 to 1320 MeV/c

Abstract

In this paper we use new data from several recent $\overline{K}N$ experiments in conjunction with older data to make an energy-dependent partial-wave analysis of the $\overline{K}N$ system. The important new additions never used before in a partial-wave analysis are our precision measurements of the charge-exchange total cross sections, our measurements of the charge-exchange angular distributions, and the first measurements of the $K^{-}p$ polarization at these low momenta. A new feature introduced in the analysis is the $S$-wave cusp treatment at the $\Lambda \eta$ and ${\Sigma }^0\eta$ thresholds, which we find necessary to describe the observed behavior in the charge-exchange total cross sections near these thresholds. Other features include a single-channel unitary formulation for resonances and backgrounds and a parametrization of these amplitudes incorporating centrifugal-barrier effects. New values for masses, widths, and elasticities for resonances in this region are reported and better evidence is found for several of the less well established resonances. None of the new resonances suggested by recent $I=0\mathrm{}$ and $I=1\mathrm{}$ total-cross-section measurements are required. Fits are displayed for all the data used and predictions of this partial-wave analysis are compared with those of two other recent analyses for certain quantities yet to be measured. A table of the amplitudes, in steps of 20 MeV/c, is provided.