Multi-quark interactions with a globally stable vacuum

Abstract

It is shown that $U(3{)}_L\times U(3{)}_R$ eight-quark interactions stabilize the asymmetric ground state of the well-known model with four-quark Nambu -- Jona-Lasinio and six-quark 't Hooft interactions. The result remains when the reduced SU(3) f\mbox{}lavour symmetry is explicitly broken by the general current quark mass term with ${\hat{m}}_u\ne {\hat{m}}_d\ne {\hat{m}}_s$.

Comments: LaTeX, 17 pages, 2 figures, version to appear in Phys. Lett. B