In the one-particle sector of Nelson’s massless model, the one-particle
states are constructed for an arbitrarily small infrared cutoff in the interaction
term of the Hamiltonian of the system. The performed method is a constructive
one which exploits only regular perturbation theory, by a suitable iteration scheme.
The disappearance of one-particle states is showed in the limit of no infrared regularization.
Constructive features, as regularity in some parameters, are also inquired.