18-22 May 2015
Wayne State University
US/Eastern timezone
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Contribution

Wayne State University - B/C, McGregor

A New Dynamical Picture for Production and Decay of the XYZ Mesons

Speakers

  • Prof. Richard LEBED

Primary authors

Abstract content

I introduce an entirely new dynamical description for tetraquark mesons, based upon the competing effects of the strong attraction between quarks in a diquark, and the inability of the diquark to hadronize on its own due to being a color nonsinglet. This mechanism naturally explains, for example, the strong preference of the Z(4475) to decay to psi(2S) rather than the J/psi, the existence of a state Y(4630) that decays to Lambda_c baryon pairs, and why some but not all exotics lie near hadronic thresholds. Owing to high-energy constituent counting rules, the four-quark nature of the states produces major changes to both the high-s scaling of cross sections for producing such states and to the potency of the cusp effect of attracting resonances to pair-production thresholds.