Peláez Sagredo, José RamónGómez Nicola, Ángel2023-06-202023-06-2019990375-947410.1016/S0375-9474(00)00225-6https://hdl.handle.net/20.500.14352/59579© Elsevier Science Bv.We report on our present work, where by means of the Inverse Amplitude Method we unitarize the elastic pion nucleon scattering amplitudes of Heavy Barion Chiral Perturbation Theory at O(q(3)). We reproduce the scattering up to the inelastic thresholds including the Delta(1232) resonance. The fitted chiral constants are rather different from those obtained by fitting the extrapolated threshold parameters for the non-unitarized theory.engjournal articlehttp://dx.doi.org/10.1016/S0375-9474(00)00225-6http://www.sciencedirect.com/http://arxiv.org/abs/hep-ph/9909568open access51-73Meson interactionsUnitarizationFísica-Modelos matemáticosFísica matemática