Dynamical study of QQ-(u)over-bar (d)over-bar mesons

It has been recently conjectured by Selem and Wilczek [1] the existence of a ss-[ud] meson due to strong correlations between the two light antiquarks. We make a detailed study of this system within a dynamical quark model which has proven to be successful in reproducing the most important features of low-energy hadron phenomenology. Our results, obtained within a parameter-free calculation, show that the antidiquark component of the ssu d system indeed entails the stronger attraction, and drives its energy much lower than the N Xi threshold, but still above the (KK*-)-K-0 or (KK-)-K-*0 thresholds. We have also studied the ccu d and bbu d systems. Exotic mesons are only expected to exist in…