Particle and Astro-Particle Physics Seminars

A New Dynamical Picture for the Production and Decay of the X, Y, Z, and P_c Charmoniumlike Exotics

by Richard Lebed (Arizona State University)

Europe/Zurich
4/3-006 - TH Conference Room (CERN)

4/3-006 - TH Conference Room

CERN

110
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Description
I introduce an entirely new dynamical description for exotic charmoniumlike hadrons, 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 X(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. The recently observed P_c^+ pentaquark candidates are seen to fit naturally into this scheme.