Observation of $Ω(2012)^- \to Ξ(1530)\bar{K}$ and measurement of the effective couplings of $Ω(2012)^-$ to $Ξ(1530)\bar{K}$ and $Ξ\bar{K}$
hep-ex
/ Authors
Belle Collaboration, S. Jia, C. P. Shen, C. Z. Yuan, J. K. Ahn, H. Aihara, D. M. Asner, H. Atmacan, R. Ayad, S. Bahinipati
and 110 more authors
Sw. Banerjee, J. Bennett, M. Bessner, D. Biswas, M. Bračko, P. Branchini, A. Budano, M. Campajola, M. -C. Chang, B. G. Cheon, H. E. Cho, S. -K. Choi, Y. Choi, S. Choudhury, G. De Pietro, R. Dhamija, F. Di Capua, J. Dingfelder, P. Ecker, D. Epifanov, T. Ferber, D. Ferlewicz, B. G. Fulsom, V. Gaur
/ Abstract
Using $Υ(1S)$, $Υ(2S)$, and $Υ(3S)$ data collected by the Belle detector, we discover a new three-body decay, $Ω(2012)^-\toΞ(1530)\bar K\toΞπ\bar K$, with a significance of 5.2~$σ$. The mass of the $Ω(2012)^-$ is $(2012.5\pm0.7\pm0.5)$ MeV and its effective couplings to $Ξ(1530)\bar{K}$ and $Ξ\bar{K}$ are $(39^{+31}_{-39}\pm9)\times10^{-2}$ and $(1.7\pm0.3\pm0.3)\times10^{-2}$, 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 $Ξ\bar{K}$ is $0.99\pm0.26\pm0.06$, assuming isospin symmetry.