Hidden-charm decays of X (3915) and Z (3930) as the P-wave charmonia
Dian-Yong Chen (Nuclear Theory Group, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China, Research Center for Hadron and CSR Physics, Lanzhou University, Institute of Modern Physics of CAS, Lanzhou 730000, China); Xiang Liu (School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China, Research Center for Hadron and CSR Physics, Lanzhou University, Institute of Modern Physics of CAS, Lanzhou 730000, China); Takayuki Matsuki (Theoretical Research Division, Nishina Center, RIKEN, Saitama 351-0198, Japan, Tokyo Kasei University, 1-18-1 Kaga, Itabashi, Tokyo 173-8602, Japan)
In this work, we investigate the and decays into with the and assignments to and , respectively. The results show that the decay width of is at least one order smaller than that of . This observation explains why only one structure, , has been observed in the invariant mass spectrum for the process .
