2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/82925It is shown that pions can be included perturbatively into effective field theory only for the external momenta, well below the pion mass. But for such low energies it is not necessary to include pions explicitly.10 pages, 4 figures. More details included, different arguments givenNuclear TheoryHigh Energy Physics - Phenomenologytext