2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198807We consider a model of quantum field theory with higher derivatives for a spinor field with quartic selfinteraction. With the help of the Bethe-Salpeter equation we study the problem of the two particle bound states in the "chain" approximation. The existence of a scalar bound state is established.14 pages, no figures, LaTeXHigh Energy Physics - Theorytext