A possible explanation of the threshold enhancement in the process e+e-→∧■

作者：肖立叶; 翁新震; 钟显辉; 朱世琳

来源：Chinese Physics C, 2019, 43(11): 53-61.

Inspired by the recent measurement of the process e+e-→∧■,we calculate the mass spectrum of the 0 meson with the GI model.For the excited vector strangeonium states ?(3 S,4 S,5 S,6 S) and ?(2 D,3 D,4 D,5 D),we investigate the electronic decay width with the Van Royen-Weisskopf formula,and the partial widths of the ∧■,■,and■ decay modes with the extended quark-pair creation model.We find that the electronic decay width of the D-wave vector strangeonium is about 3～8 times larger than of the S-wave vector strangeonium.Around 2232 Me V,the partial decay width of the ∧■ mode can be up to several MeV for ?(33 S1),while the partial ∧■ decay width of ?(23 D1) is O(10-3) keV.If the threshold enhancement reported by the BESIII collaboration arises from the strangeonium meson,this state is very likely the ?(33 S1) state.We also note that the ∧■ and∑+■partial decay widths of the states ?(33 D1) and ?(43 S1) are several MeV,which is sufficient to be observed in future experiments.

• 单位
  核物理与核技术国家重点实验室; 北京大学