Implications of heavy quark spin symmetry on heavy meson hadronic molecules

Abstract

In recent years, many heavy mesons and charmonia were observed which do not fit in the conventional quark model expectations. Some of them are proposed to be hadronic molecules. Here we investigate the consequences of heavy quark spin symmetry on these heavy meson hadronic molecules. Heavy quark spin symmetry enables us to predict new heavy meson molecules and provides us with a method to test heavy meson molecule assumptions of some newly observed states. In particular, we predict an η_c'f_0(980) bound state as the spin-doublet partner of the Y(4660) proposed as a ψ'f_0(980) bound state with a mass of 4616^{+5}_{-6} MeV and the prominent decay mode η_c'ππ. The width is predicted to be Γ(η_c'ππ)=60\pm30 MeV. The pi^+π^- invariant mass spectrum and the line shape are calculated. We suggest to search for this state in B^{\pm}-->η_c'K^{\pm}π^+π^-, whose branching fraction is expected to be large.