Evidence of $\hat{I}º$ particle in $J/\ddot{I}ˆ\to {\bar{K}}^{\ast }(892{)}^0{K}^{+}\ddot{I}{€}^{-}$

Abstract

Based on a $J/\ddot{I}ˆ$ data sample of $7.8\times 10^6$ events at BESI, the decay of $J/\ddot{I}ˆ\to {\bar{K}}^{\ast }(892{)}^0{K}^{+}\ddot{I}{€}^{-}$ is studied and a low mass enhancement, which is believed not coming from the phase space effect or background, is visible in the $K^{+}\ddot{I}{€}^{-}$ invariant mass spectrum recoiling against ${\bar{K}}^{\ast }(892{)}^0$. Partial wave analysis of this channel favors this low mass enhancement being a broad $0^{+}$ resonance with the mass and width of $771_{-221}^{+164}\pm 55$ MeV/c${}^2$ and $220_{-169}^{+225}\pm 97$ MeV/c${}^2$, respectively.

4 pages, 4 figures