Prof. Javier Vijande (university of Valencia)
The problem of the stability of mesons and baryons against their decay into lighter hadrons has been widely discussed in the literature. During the last years it has been suggested the potential role played by higher-order many-quark configurations in the hadron spectra. These terms are a reflection of the involved color structure present in hadrons and they might be described either in terms of pairwise or non-pairwise interactions. Their stability against the decay into lighter mesons and baryons is an important spectroscopic ingredient. In this talk we focus on the role played by four- and six-quark configurations using both pairwise and non-pairwise interactions. Four-quark components are good candidates to describe some of the new measured states in the charm sector while the existence of six-quark states, either baryonium or baryon-baryon configurations, have been an ongoing matter of debate since the late seventies .  T.F. Carames, A. Valcarce, J. Vijande, Phys.Rev.D82:054032,2010; Phys.Rev.Lett.103:222001,2009. J. Vijande, A. Valcarce, Phys.Rev.C80:035204,2009. J. Vijande, A. Valcarce, et al, Phys.Rev.D79:074010,2009; Phys.Rev.D76:114013,2007.