Solution of the dispersion relations for the πNscattering amplitudes by the method of Padé approximants
Abstract
The [1, 1] Padé approximant is used in order to obtain a solution of the dispersion relations for the πNscattering amplitude. The dispersion relations are constructed with one subtraction for the amplitude A^{(+)} and without subtraction for all the other amplitudes. There is one free parameter (β) only, connected with the tchannel contribution. The results obtained for s, p and d waves with isospin T= {1}/{2}and T= {3}/{2} are in satisfactory agreement with experiment in quite a large energy region (except the P _{13} wave). The results of the calculations do not change very much if one neglects the contribution of the tchannel ( β=0). The partial S_{l± }^{(2 t) } matrix analysis in the region below the threshold of πNscattering indicates the existence of antibound states in the P _{33} wave with effective masses of 900 and 955 MeV and in the P _{11} wave with an effective mass of1010 MeV.
 Publication:

Nuclear Physics B
 Pub Date:
 June 1972
 DOI:
 10.1016/05503213(72)90497X
 Bibcode:
 1972NuPhB..42..541F