Observation of $\hat{I}\text{c◯}(2012{)}^{-}\to \hat{I}ž(1530)\bar{K}$ and measurement of the effective couplings of $\hat{I}\text{c◯}(2012{)}^{-}$ to $\hat{I}ž(1530)\bar{K}$ and $\hat{I}ž\bar{K}$

Abstract

Using $\hat{I}\yen (1S)$, $\hat{I}\yen (2S)$, and $\hat{I}\yen (3S)$ data collected by the Belle detector, we discover a new three-body decay, $\hat{I}\text{c◯}(2012{)}^{-}\to \hat{I}ž(1530)\bar{K}\to \hat{I}ž\ddot{I}€\bar{K}$, with a significance of 5.2~$\ddot{I}ƒ$. The mass of the $\hat{I}\text{c◯}(2012{)}^{-}$ is $(2012.5\pm 0.7\pm 0.5)$ MeV and its effective couplings to $\hat{I}ž(1530)\bar{K}$ and $\hat{I}ž\bar{K}$ are $(39_{-39}^{+31}\pm 9)\times 10^{-2}$ and $(1.7\pm 0.3\pm 0.3)\times 10^{-2}$, where the first uncertainties are statistical and the second are systematic. The ratio of the branching fraction for the three-body decay to that for the two-body decay to $\hat{I}ž\bar{K}$ is $0.99\pm 0.26\pm 0.06$, assuming isospin symmetry.

6 pages, 4 figures, add more Omega(2012) three-body decay modes, updated version