Paper detail

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

We present a new dynamical picture that identifies the formation of the exotic $\bar c c$-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.