Hidden-charm and radiative decays of the Z(4430) as a hadronic D_1 \bar{D^\ast} bound state

Abstract

We study the $Z^{\pm }(4430)$ meson within a heavy hadron molecule interpretation where the $Z$ is considered as a bound state of a vector $D^{\ast }(2010)$ and an axial-vector $D_1(2420)$. We give predictions for the strong hidden-charm $Z^{\pm }(4430)\to {\pi }^{\pm }\psi$ and ${\pi }^{\pm }{\psi }^{\prime }$ decay widths and also study the radiative $Z^{\pm }(J^P=1^{-})\to {\pi }^{\pm }\gamma$ decay properties in a phenomenological Lagrangian approach. Our findings are qualitatively in line with the experimental observation that the ${\pi }^{\pm }{\psi }^{\prime }$ transition dominates over the ${\pi }^{\pm }\psi$ decay mode despite a smaller phase space. The width for the radiative mode ${\pi }^{\pm }\gamma$ is sizable, allowing possible detection in future experiments.

Comments: 13 pages, 3 figures, matches published version