Investigating $\eta^\prime_{1}(1855)$ exotic states in $J/\psi\to\eta^\prime_{1}(1855)\eta^{(\prime)}$ decays

TL;DR

This paper investigates the exotic $ ext{eta}_1(1855)$ state in $J/\psi$ decays, proposing a molecular state interpretation and predicting branching ratios for future experimental validation.

Contribution

It introduces a model where the $ ext{eta}_1(1855)$ is a $K ar{K}_1(1400)$ molecular state and predicts specific decay branching ratios for $J/\psi$ decays involving this state.

Findings

Predicted branching ratio for $J/\psi \to \eta'_1(1855) \eta$ is approximately $6.3 \times 10^{-6}$.

Predicted branching ratio for $J/\psi \to \eta'_1(1855) \eta'$ is approximately $6.5 \times 10^{-6}$.

The proposed mechanism involves final state interactions with $K$ and $K^*$ exchanges.

Abstract

An analysis of the $J/\psi\to \eta\eta^\prime\gamma$ decay by the BESIII collaboration claims the observation of an exotic state $\eta_1(1855)$ with $I^GJ^{PC}=0^+1^{-+}$. To establish its C-parity partner $\eta^\prime_{1}(1855)$ in the picture of the $K \bar{K}_1(1400)$ molecular state, we propose that $J/\psi\to\eta^\prime_{1}(1855)\eta^{(\prime)}$ receives the main contributions from the final state interaction of $KK^*$($K^+ K^{*-}$, $K^- K^{*+}$, $K^0 \bar{K}^{*0}$, and $\bar{K}^0 K^{*0}$). Specifically, $K$ and $K^*$ in $J/\psi\to KK^*$ decays transform as $\eta^\prime_{1}(1855)\eta^{(\prime)}$, by exchanging a $K_1(1400)$. We predict ${\cal B}(J/\psi\to \eta^{\prime}_1(1855)\eta)=(6.3^{+12.6}_{-3.5})\times 10^{-6}$, and ${\cal B}(J/\psi\to \eta^{\prime}_1(1855)\eta^{\prime}) =(6.5^{+6.6}_{-4.6})\times 10^{-6}$, which can be studied in the $J/\psi\to K^*\bar{K}^*\eta^{(\prime)}$ decays.