Compositeness and several applications to exotic hadronic states with heavy quarks

Abstract

Several methods for studying the nature of a resonance are applied to resonances recently discovered in the bottonomium and charmonium sectors. We employ the effective-range expansion, the saturation of the width and compositeness of a resonance, as well as direct fits to data. The latter stem from generic S -matrix parameterization that account for relevant dynamical features associated to channels that couple strongly in an energy region around the resonance masses, in which their thresholds also lie. We report on results obtained with these methods for the resonances Zb(10610), Zb(10650), Zcs(3985), Zc(3900), X(4020), X(6900), X(6825), and Pcs(4459).