Exclusive production of the X(3872) in B meson decay

If the recently discovered charmoniumlike state X(3872) is a loosely bound S-wave molecule of the charm mesons D0D*0 or D*0D0, it can be produced through the weak decay of the B meson into D0D*0K or D*0D0K followed by the coalescence of the charm mesons at a long-distance scale set by the scattering length of the charm mesons. The long-distance factors in the amplitude for the decay B→XK are determined by the binding energy of X, while the short-distance factors are essentially determined by the amplitudes for B→D0D*0K and B→D*0D0K near the thresholds for the charm mesons. We obtain a crude determination of the short-distance amplitudes by analyzing data from the BABAR Collaboration on the branching fractions for B→D(*)D(*)K using a factorization assumption, heavy-quark symmetry, and isospin symmetry. The resulting order-of-magnitude estimate of the branching fraction for B+→XK+ is compatible with observations provided that J/ψπ+π- is a major decay mode of the X. The branching fraction for B0→XK0 is predicted to be suppressed by more than an order of magnitude compared to that for B+→XK+