2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/194704We consider pion interactions in an effective field theory of the narrow resonance X(3872), assuming it is a weakly bound molecule of the charm mesons D^{0} \bar D^{*0} and D^{*0} \bar D^{0}. Since the hyperfine splitting of the D^{0} and D^{*0} is only 7 MeV greater than the neutral pion mass, pions can be produced near threshold and are non-relativistic. We show that pion exchange can be treated in perturbation theory and calculate the next-to-leading-order correction to the partial decay width Γ[X \to D^0 \bar D^{0} π^0].26 pages, 11 figures, revtex4, to appear in Phys. Rev. DHigh Energy Physics - PhenomenologyHigh Energy Physics - ExperimentNuclear Theorytext