Revealing the inner structure of the newly observed ${\eta }_1(1855)$ via photoproduction

Abstract

Very recently, a new hadronic exotic state ${\eta }_1(1855)$ at the invariant mass spectrum of $\eta {\eta }^{{}^{\prime }}$ was observed by the BESIII Collaboration. According to its properties, such as the spectroscopy and decay width, the ${\eta }_1(1855)$ have been suggested to be a compact multi-quark state, a hadron molecule, or a hybrid meson. In order to distinguish the various interpretations of the ${\eta }_1(1855)$, a Reggeized model combined with the vector dominance model for ${\eta }_1(1855)$ photoproduction on the proton target is presented. If the ${\eta }_1(1855)$ is a $s\bar{s}g$ hybrid meson, the ${\eta }_1(1855)$ can be produced though the Primakoff effect. However, the ${\eta }_1(1855)$ photoproduction is dominated by the $t$-channel vector mesons $\rho$, $\omega$, and $\varphi$ exchange by assuming ${\eta }_1(1855)$ as an $S$-wave $K{\bar{K}}_1(1400)$ molecular state. Our calculations show that the total cross section of the ${\eta }_1(1855)$ production via $\gamma p$ reaction can reach up to 0.115 pb, about 0.0124$\%$ of the total cross section obtained by considering the ${\eta }_1(1855)$ as an $S$-wave $K{\bar{K}}_1(1400)$ molecule. We also find their line shapes are sizably different. If the ${\eta }_1(1855)$ is a molecular state, the photoproduction of ${\eta }_1(1855)$ near the threshold offers a nice place to test its molecular nature. However, it should be better to take high energy, at least above $E_{\gamma }=16.97$ GeV, to observe the production of ${\eta }_1(1855)$ if ${\eta }_1(1855)$ is a $s\bar{s}g$ hybrid meson. These results can be measured in the GlueX experiment or Electron-Ion Collider in China to test the nature of the ${\eta }_1(1855)$.

References in corpus (13)

• Hybrid Mesons
• Study of $P_c(4457)$, $P_c(4440)$, and $P_c(4312)$ in a quasipotential Bethe-Salpeter equation approach
• Isospin breaking decays as a diagnosis of the hadronic molecular structure of the $P_c(4457)$
• Possible structure of the newly found exotic state ${\eta }_1(1855)$
• Towards the establishment of the light $J^{P(C)}=1^{-(+)}$ hybrid nonet
• $S$- and $P$-wave fully-strange tetraquark states from QCD sum rules
• The phenomenology of the exotic hybrid nonet with ${\pi }_1(1600)$ and ${\eta }_1(1855)$
• QCD axial anomaly enhances the $\eta {\eta }^{\prime }$ decay of the hybrid candidate ${\eta }_1(1855)$
• Analysis of the ${\eta }_1(1855)$ as a $K{\bar{K}}_1(1400)$ molecular state
• $1^{-+}$ Hybrid in $J/\psi$ Radiative Decays from Lattice QCD
• Exclusive photoproduction of $f_1(1285)$ meson off proton in the JLab kinematics
• Regge phenomenology in ${\pi }^0$ and $\eta$ photoproduction
• Radiative production and decays of the exotic ${\eta }_1^{\prime }(1855)$ and its siblings

Cited by in corpus (4)

• Constructing the $J^{P(C)}=1^{-(+)}$ light flavor hybrid nonet with the newly observed ${\eta }_1(1855)$
• Predictions of the hybrid mesons with exotic quantum numbers $J^{PC}=2^{+-}$
• Mixing angle of $K_1(1270/1400)$ and the $K{\bar{K}}_1(1400)$ molecular interpretation of ${\eta }_1(1855)$
• Light tetraquark states with exotic quantum numbers $J^{PC}=2^{+-}$