Interpretation of the η1(1855) as a K■1(1400) + c.c. molecule

作者：Xiang-Kun Dong; Yong-Hui Lin; Bing-Song Zou

来源：Science China Physics,Mechanics & Astronomy, 2022, 65(06): 64-70.

An exotic state with JPC= 1-+, denoted by η1(1855), was observed by BESⅢ Collaboration recently in J/ψ → γηη′. The fact that its mass is just below the threshold of K■1(1400) stimulates us to investigate whether this exotic state can be interpreted as a K■1(1400) + c.c. molecule or not. Using the one boson exchange model, we show that it is possible for K■1(1400) with JPC= 1-+to bind together by taking the momentum cutoff Λ ≥2 Ge V and yield the same binding energy as the experimental value when Λ ≈ 2.5 GeV. In this molecular picture, the predicted branch ratio Br(η1(1855) → ηη′) ≈ 15% is consistent with the experimental results, which again supports the molecular explanation of η1(1855). Relevant systems, namely K■1(1400) with JPC= 1--and K■1(1270) with JPC= 1-±, are also investigated, some of which can be searched for in the future experiments.

• 单位
  中国科学院大学; 中南大学