2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/56655In the one nucleon sector of Nelson's massless model with an ultraviolet cut-off and no infrared regularization, one particle improper states are constructed and a scattering theory is developed both for the massless scalar field and for the non-relativistic particle.121 pages, 1 Postscript figureMathematical Physicstext