Hidden-charmonium decays of $Z_c(3900)$ and $Z_c(4025)$ in intermediate meson loops model

Abstract

The BESIII collaboration reported an observation of two charged charmonium-like structure $Z_c^{\pm }(3900)$ and $Z_c^{\pm }(4025)$ in $e^{+}{e}^{-}\to (J/\psi \pi {)}^{\pm }{\pi }^{\mp }$ and $e^{+}{e}^{-}\to (D^{\ast }{\bar{D}}^{\ast }{)}^{\pm }{\pi }^{\mp }$ at $\sqrt{s}=4.26$ GeV recently, which could be an analogue of $Z_b(10610)$ and $Z_b(10650)$ claimed by the Belle Collaboration. In this work, we investigate the hidden-charmonium transitions of $Z_c^{\pm }(3900)$ and $Z_c^{\pm }(4025)$ via intermediate $D^{(\ast )}{D}^{(\ast )}$ meson loops. Reasonable results for the branching ratios by taking appropriate values of $\alpha$ in this model can be obtained, which shows that the intermediate $D^{(\ast )}{D}^{(\ast )}$ meson loops process may be a possible mechanism in these decays. Our results are consistent with the power-counting analysis, and comparable with the calculations in the framework of nonrelativistic effective field theory to some extent. We expect more experimental measurements on these hidden-charmonium decays and search for the decays of $Z_c\to D{\bar{D}}^{\ast }+c.c.$ and $Z_c^{\prime }\to D^{\ast }{\bar{D}}^{\ast }$, which will help us investigate the $Z_c^{(\prime )}$ decays deeply.

Comments: 8 pages, 9 figures; Accepted by Eur. Phys. J. C. arXiv admin note: text overlap with arXiv:1212.3784