Molecular states of heavy quark mesons

We explore molecular states of two open heavy-quark mesons (Q(q) over bar) -- (q) in a quark-based model in terms of a four-body nonrelativistic Hamiltonian with pairwise effective interactions. Molecular states are found in the combinations of {D, D*, B, B*} with {(D) over bar(D) over bar,*(B) over bar(B) over bar*}, including a weakly bound D(D) over bar* state near the threshold which may be qualitatively identified as the 3872 state observed recently by the Belle Collaboration.