Measurements of Ω− branching fractions

T Xiao,Kamal K Seth,A Tomaradze,S Dobbs

doi:10.1103/physrevd.98.012007

Abstract

Using $e^+e^-$ annihilation data taken at the CESR collider with the CLEO-c detector, measurements of two main $\Omega^-$ branching fractions have been made using the reaction $\psi(2S)\to\Omega^-\overline{\Omega}^+$, hyperon pair production at $\sqrt{s}=3.69$~GeV, the peak of the $\psi(2S)$ resonance. $\Omega^-$ decay channels are identified through momentum distributions of charged particles, and systematics of the $\Omega^-$ branching fractions have been studied. The result gives: $\mathcal{B}(\Omega^- \to \Lambda^0 K^-) = (68.9\pm9.5\pm4.3)\%$, and $ \mathcal{B}(\Omega^- \to \Xi^0 \pi^-) = (19.0\pm4.0\pm1.2)\%$.

Highlights

Experimental data for the Ω− hyperon (S 1⁄4 −3) are much more sparse than for the Λ and Σ (S 1⁄4 −1), and Ξ (S 1⁄4 −2) hyperons
In a recent paper [4], we have reported the first measurements of Λ, Σþ0, Ξ−0, and Ω− hyperons in their production in eþe− annihilation at CLEO
Compared to the hyperon beam measurement of CERN we identified far fewer Ω− (N 1⁄4 326 Æ 19), since no other measurements of the branching fractions of Ω− have been reported, we consider it important to report the results of our independent measurements of the branching fractions for the two-body decays of Ω− to Λ0K− and Ξ0π−

Summary

INTRODUCTION

Experimental data for the Ω− hyperon (S 1⁄4 −3) are much more sparse than for the Λ and Σ (S 1⁄4 −1), and Ξ (S 1⁄4 −2) hyperons. The major branching fractions for Ω− decay have only been measured at the hyperon beam constructed at the CERN SPS (Super Proton Synchrotron), first in 1979 [1,2] and later at higher energy in 1984 [3]. In the 1984 measurement, 16,000 Ω− were identified, and the branching fractions Ω− → Λ0K−, Ω− → Ξ0π−, and Ω− → Ξ−π0 were reported. Compared to the hyperon beam measurement of CERN we identified far fewer Ω− (N 1⁄4 326 Æ 19), since no other measurements of the branching fractions of Ω− have been reported, we consider it important to report the results of our independent measurements of the branching fractions for the two-body decays of Ω− to Λ0K− and Ξ0π−

DATA SAMPLES AND EVENT SELECTIONS

RESULTS

SYSTEMATIC UNCERTAINTIES