The $X(3872) \to J/\psi \gamma$ decay in the $D \bar D^*$ molecular picture

Understand

From a picture of the X(3872) where the resonance is a bound state of $\bar{D}D^*-c.c.$, we evaluate the decay width into the $J/\psi \gamma$ channel, which is sensitive to the internal structure of this state.

• For this purpose we evaluate the loops through which the X(3872) decays into its components, and the $J/\psi$ and the photon are radiated from these components.
• We use the local hidden gauge approach extrapolated to SU(4) with a particular SU(4) breaking.
• The radiative decay involves anomalous couplings and we obtain acceptable values which are compared to experiments and results of other calculations.