Radiative transitions of charmoniumlike exotics in the dynamical diquark model

Using the dynamical diquark model, we calculate the electric-dipole radiative decay widths to X(3872) of the lightest negative-parity exotic candidates, including the four I=0, JPC=1 - ("Y") states. The O(100-1000 keV) values obtained test the hypothesis of a common substructure shared by all of these states. We also calculate the magnetic-dipole radiative decay width for Zc(4020)0→γX(3872), and find it to be rather smaller (<10 keV) than its predicted value in molecular models.