Nature of $K^*(1680)$ and $q\bar{q}$-hybrid mixing as the SU(3) partner of $η_{1}(1855)$ in the strange sector

Abstract

We presents an investigation of the $K^*(1680)$ state in its strong decays into two-body finial states within the flux-tube model and quark pair creation model. Since the charge conjugation parity is not conserved in the strange sector, the conventional $q\bar{q}$ states of $J^{P(C)}=1^{-(-)}$ can mix with the lowest hybrid states with $J^{P(C)}=1^{-(+)}$. Our analysis of the $K^*(1680)$ two-body strong decays indicates that the decay pattern of $K^*(1680)$ cannot be explained by the conventional $q\bar{q}$ scenario. Meanwhile, strong evidence shows the $q\bar{q}$-hybrid mixing mechanism in the strange sector. The phenomenological consequences of such a mixing are also discussed. Our study can provide a guidance for the future search for hybrid multiplets in experiment at BESIII, LHCb, and Belle-II.

Figures (3)

• Figure 1: Schematic illustrations for the two-body hadronic decays of hybrid states. (a) is dominated by the collinear mode, and (b) is dominated by the transverse mode.
• Figure 2: Illustrations of the strong decays of $K^*(1680)$ as a $q\bar{q}$ into $PP$ or $PV$ in the QPC model. The collinear mode of a hybrid decay via Fig. \ref{['Fig:FT']} (a) cannot be distinguished from the QPC mechanism shown here.
• Figure 3: (a) The fitted mixing angle $\zeta$ for different $\gamma_2$ values: $\gamma_2=5,\ 6,\ 7,\ 8,$ and $9$ with $\delta=1.2$. (b) Partial decay widths for the four decay modes $K\pi$, $K\eta$, $K^*\pi$, and $K\rho$ are fitted by the mixing angle $\zeta$ with $\gamma_2=5,\ 6,\ 7,\ 8$, and $9$ and $\delta=1.2$.