Using the decay \psi(4160) -> X(3872) \gamma\ to probe the molecular content of the X(3872)

Abstract

The X(3872) has non-charmonium-like properties, such as decay processes that seem to violate isospin, and a mass that lies unexpectedly close to the neutral-D-plus-neutral-D-excited-state threshold. An EFT that includes both charmonium-like (short distance) and molecule-like (meson bound state) properties is used to analyze the X(3872) as it is produced in the decay of \psi(4160). This is a route that BESIII may be able to measure. We find that the correlation between the angular distribution of the outcoming photon (or X(3872)) and the polarization of the \psi(4160) source may be used to provide information on whether short-distance or long-distance effects dominate.