We report a new measurement of the decay \Omega^- \to \Xi^- \pi^+ \pi^- with 76 events and a first observation of the decay \Omega^+ \to \Xi^+ \pi^+ \pi^- with 24 events, yielding a combined branching ratio (3.74 ^{+0.67}_{-0.56}) \times 10^{-4}. This represents a factor 25 increase in statistics over the best previous measurement. No evidence is seen for CP violation, with B(\Omega^- \to \Xi^- \pi^+ \pi^-)=4.04^{+0.83}_{-0.71} \times 10^{-4} and B(\Omega^+ \to \Xi^+ \pi^+ \pi^-)=3.15^{+1.12}_{-0.89} \times 10^{-4}. Contrary to theoretical expectation, we see little evidence for the decays \Omega^- \to \Xi_{1530}^{*0} \pi^- and \Omega^+ \to \Xi_{1530}^{*0} \pi^+ and place a 90% C.L. upper limit on the combined branching ratio B(\Omega^-(\Omega^+) \to \Xi^{*0}_{1530}(\Xi^{*0}_{1530}) \pi^\mp)<7.0 \times 10^{-5}.
@article{arxiv.1008.4405,
title = {Study of the rare hyperon decay Omega \to Xi \pi^+ \pi^-},
author = {HyperCP Collaboration and O. Kamaev and N. Solomey and R. A. Burnstein and A. Chakravorty and Y. C. Chen and W. -S. Choong and K. Clark and E. C. Dukes and C. Durandet and J. Felix and Y. Fu and G. Gidal and H. R. Gustafson and T. Holmstrom and M. Huang and C. James and C. M. Jenkins and T. D. Jones and D. M. Kaplan and M. J. Longo and L. C. Lu and W. Luebke and K. -B. Luk and K. S. Nelson and H. K. Park and J. -P. Perroud and D. Rajaram and H. A. Rubin and J. Volk and C. G. White and S. L. White and P. Zyla},
journal= {arXiv preprint arXiv:1008.4405},
year = {2014}
}
Comments
6 pages, 5 figures, to be published in Phys. Lett. B