Researchers at Institute of Modern Physics, Chinese Academy of Sciences (IMP) explored the discovery potential of the X(3915) in meson photoproduction process, which is a different production mechanism in studying the X(3915) and P-wave charmonium. It’s helpful to further study of X(3915).

The X(3915) is a typical charmoniumlike state, which was first observed in the  invariant mass spectrum of . Since X(3915) could be produced in the  fusion process, its possible spin-parity assignment is either J^p=0⁺ or J^p=2⁺ . Later, BABAR carried out a spin-parity analysis of X(3915), which supported the J^p=0⁺assignment due to the resonance.

The X(3915) as a   state brings a new problem. A state dominantly decays into . Until now the X(3915) signal has been missing in the invariant mass spectrum given by Belle and BABAR in . Some research proposed that the Z(3930) enhancement may contain two P-wave higher charmonia and . The numerical result shows that this assumption is supported by the analysis of the invariant mass spectrum. Thus, there is no difficulty in this explanation of X(3915). However, the inner structure of X(3915) is still unknown. It is obvious that the production of X(3915) in different processes other than the fusion is an interesting research topic.

Researchers explored the production of the charmoniumlike state X(3915) in the photoproduction process . The numerical result indicated that the maximum of the calculated total cross section of could reach up to the order of 10nb.

Furthermore, the Dalitz plot analysis was performed by considering the Pomeron exchange as the background contribution. This analysis showed that the X(3915) signal could be distinguished from the background easily and the best energy window of searching for X(3915) is or  with different decay width 1.7 MeV or 5.1 MeV, which is the important information for further experimental study of X(3915) by meson photoproduction.

The work has been published in Phys. Rev. D.89, 034016 (2014).

Fig. 1 The energy dependence of the total cross sections for (Image by IMP)