Novel charmonium and bottomonium spectroscopies due to deeply bound hadronic molecules from single pion exchange

Pion exchange in S-wave between hadrons that are themselves in a relative S-wave is shown to shift energies by hundreds of MeV, leading to deeply bound quasimolecular states. In the case of charmed mesons D*, D₁ a spectroscopy arises consistent with enigmatic charmonium states observed above 4 GeV in e⁺e^- annihilation. A possible explanation of Y(4260)→ψππ and Y(4360)→ψ^'ππ is found. We give results for all isospin and charge-conjugation combinations, and comment on flavor exotic doubly charmed states and bottomonium analogs. A search in DD̄3π is recommended to test this hypothesis. An exotic 1^-+ is predicted to occur in the vicinity of the $Y(4260)$.