X(3872)→J/ψγ decay in the DD̄* molecular picture

Abstract

From a picture of the X(3872) where the resonance is a bound state of D̄D*-c.c., we evaluate the decay width into the J/ψγ 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/ψ 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. Simultaneously, we evaluate the decay rate for the X(3872) into J/ψω and J/ψρ, and the results obtained for the ratio of these decay widths are compatible with the experiment. We also show that considering only the D̄0D*0-c.c. component in the radiative decay reduces the partial decay width in more than three orders of magnitude, in large discrepancy with experiment. © 2012 American Physical Society.