Instantons and Structure of Pentaquark
  We are discussing the influence of the complex structure of the QCD vacuum on the properties of the exotic multiquark states, specially the possibility for the existence of a deeply bound pentaquark. We show that the specific spin-flavor properties of the instanton induced interaction between the quarks leads to the existence of light tri- and di-quark clusters inside the pentaquark. This strong quark correlations might be behind the anomalous properties of the pentaquark. 
Hee-Jung Lee