Instanton induced quark dynamics and the pentaquark

AbstractWe analyze the existence of the exotic Θ+ from the perspective of instanton induced quark dynamics. The 't Hooft interaction gives strong attraction in specific channels of the triquark uds̄ and diquark ud configurations. In particular it leads to a light uds̄ triquark cluster, with the mass around 750 MeV, in the I=0, S=1/2 and color 3 configuration, and a light ud-diquark configuration, with mass 440 MeV, in the I=0, S=0 and color 3̄ configuration. If we consider the pentaquark as a bound state of such triquark and diquark configurations in a relative L=1 state we obtain good agreement with the data. The small width of Θ+ has a natural explanation in this model