2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/193251A simple string model inspired by the strong-coupling regime of Quantum ChromoDynamics is used as a potential for studying the spectrum of multiquark systems with two quarks and two antiquarks, with a careful treatment of the four-body problem. It is found that the ground state is stable, lying below the threshold for dissociation into two isolated mesons.4 pages, 2 figures, Refs. added, typos corrected, discussion improved, to appear in Phys. Rev. DHigh Energy Physics - PhenomenologyNuclear Theorytext