Implications of a DK molecule at 2.32 GeV

We discuss the implications of a possible quasinuclear DK bound state at 2.32 GeV. Evidence for such a state was recently reported in Dₛ⁺π⁰ by the BaBar Collaboration. We first note that a conventional quark model cs̄ assignment is implausible, and then consider other options involving multiquark systems. An $I=0$ cs̄nn ̄ \= baryonium assignment is one possibility. We instead favor a DK meson molecule assignment, which can account for the mass and quantum numbers of this state. The higher-mass scalar cs̄ state expected at 2.48 GeV is predicted to have a very large DK coupling, which would encourage formation of an $I=0$ DK molecule. Isospin mixing is expected in hadron molecules, and a dominantly $I=0$ DK state with some $I=1$ admixture could explain both the narrow total width of the 2.32 GeV state as well as the observed decay to Dₛ⁺π⁰. Additional measurements that can be used to test this and related scenarios are discussed.