A New Picture for the Formation and Decay of the Exotic XY Z Mesons

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We present a new dynamical picture that identifies the formation of the exotic c c-containing states XY Z with the confinement-induced hadronization of a rapidly separating pair of a compact diquark and antidiquark. This picture combines the advantages of diquark-based models, which can accommodate much of the known XY Z spectrum, with the experimental fact that such states are both relatively narrow and are produced promptly. It also naturally explains the preference of some of the exotic states to decay to ψ(2S), rather than J/ψ, in terms of a simple wave-function overlap effect.