Any recommendation? I have found this one very spectacular: hep-ph/0404270 Eberhard Klempt Glueballs, Hybrids, Pentaquarks : Introduction to Hadron Spectroscopy and Review of Selected Topics Myself I am having some interest on diquarks but from a peculiar point of view about family symmetry. Usually scalar diquarks are pictured as antisymmetric both in spin and flavour. But if you separate flavour into isospin plus family the situation is more complicated, and becomes worse if you want consider weak isospin, which is chiral. My hope/conjecture for the outcome is that Q=4/3 scalar diquarks are still forbidden, but Q=2/3 become allowed. The current view only allows for Q=2/3 scalar diquarks when families are mixed, for instance (ds), but not (dd).