What can radiative decays of the X(3872) teach us about its nature?

Abstract

Starting from the hypothesis that the X(3872) is a $D{\bar{D}}^{\ast }$ molecule, we discuss the radiative decays of the X(3872) into $\gamma J/\psi$ and $\gamma {\psi }^{\prime }$ from an effective field theory point of view. We show that radiative decays are very weakly sensitive to the long-range structure of the X(3872). In particular, contrary to earlier claims, we argue that the experimentally determined ratio of the mentioned branching fractions is not in conflict with a wave function of the X(3872) that is dominated by the $D{\bar{D}}^{\ast }$ hadronic molecular component.

Comments: LaTeX2e, 10 pages, 1 figure, 2 tables, version ot appear in Phys.Lett.B