If the quantum numbers of the X(3872) are J^{ PC}=1^{ ++}, the measurement of its mass implies that it is either a loosely-bound hadronic molecule whose constituents are a superposition of the charm mesons pairs D^{ *0} Dbar^0 and D^0 Dbar^{ *0} or else it is a virtual state of these charm mesons. Its binding energy is small enough that the decay width of a constituent D^{ *0} or Dbar^{ *0} has a significant effect on the line shapes of the X resonance. We develop a simple approximation to the line shapes that takes into account the effect of the D^{ *0} width as well as inelastic scattering channels of the charm mesons. We carry out a simultaneous fit to the line shapes in the J/psi pi^+ pi^- and D^0 Dbar^0 pi^0 channels measured in the decays B^+ to K^+ + X by the Belle Collaboration. The best fit corresponds to the X(3872) being a bound state just below the D^{ *0} Dbar^0 threshold, but a virtual state just above the D^{ *0} D-ar^0 threshold is not excluded.
Categories: hep-ph