Fixedu FiniteEnergySumRule Calculations and the CERN πN Amplitudes
Abstract
It is shown that Regge asymptotic πN scattering amplitudes constructed from the CERN modelindependent experimental (EXP) phase shifts possess better convergence properties than the same amplitudes constructed from the CERN resonancemodel dispersionrelation (TH) phases used previously in fixedu finiteenergy sum rules. The EXP phases provide a better description of the πN data since they are fitted to them directly, while the TH phases are only an attempt to approximate the EXP phases by a resonance model satisfying dispersionrelation constraints. However, substituting the EXP phases for the TH ones does not greatly alter the sumrule results. The calculations are also extended to higher moments and suggestions are made for improving the calculation.
 Publication:

Physical Review D
 Pub Date:
 November 1970
 DOI:
 10.1103/PhysRevD.2.2096
 Bibcode:
 1970PhRvD...2.2096S