Elastic scattering analyses and dispersion relation constraints
  We present the results of energy-dependent and single-energy partial-wave analyses of pi-N elastic scattering data with laboratory kinetic energies below 2.1 GeV. We have considered the effect of adding dispersion-relation constraints required for a more reliable extraction of the pi-N sigma term. The results of these new fits are compared with those generated previously, using a reduced set of constraints, and with a fit which has only utilized forward constraints associated with the S-wave scattering lengths. We compare the results in terms of their resonance spectra and preferred values for the pi-N-N coupling and pi-N sigma term. 
R.A. Arndt, I.I. Strakovsky, R.L. Workman, and M.M. Pavan