A New Picture for the Formation and Decay of the Exotic $XYZ$ Mesons

Abstract

We present a new dynamical picture that identifies the formation of the exotic $\bar{c}c$-containing states $XYZ$ 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 $XYZ$ 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 $\psi (2S)$, rather than $J/\psi$, in terms of a simple wave-function overlap effect.

5 pages, 4 .eps figures, ReVTeX. References added

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