Barnes, V.E. et al. Confirmation of the Existence of the ^{–} Hyperon
Phys. Lett. 12 (1964) 134;

Reprinted in
(translation into Russian) Usp. Fiz. Nauk 85 (1965) 523.

Abstracts
In a recent publication we have reported evidence for the existence of a new negatively charged hyperon with strangeness S = -3, and mass M = 1686 ± 12 MeV/c^{2} which decayed weakly into a ^{o} and ^{–}. This particle was identified with the ^{–} predicted by the Unitary Symmetry scheme of strong interactions proposed by Gell-Mann and Ne'eman.
In this model, based on the 8 dimensional representation of SU(3), the strongly interacting particles are identified with the basis vectors of the irreducible representations in the direct product 8 x 8. Each representation consists of states with the same spin-parity; the hypercharge and I_{3} (third component of isospin) quantum numbers serve as labels of the states within the representation. One such representation is the 10 dimensional representation, nine of whose members are associated
with the well known resonances N^{*}_{3/2}, Y^{*}_{1}, ^{*}_{1/2} (all with spin-parity J^{P} = 3/2^{+}). The tenth member, the ^{–}, is predicted to be a negatively charged isosinglet with strangeness minus three and the same spin-parity as the other numbers of the multiplet, namely 3/2^{+}. Also, the ^{–}
mass is predicted to be 1676 MeV/c^{2} by the Gell-Mann-Okubo mass formula. In this letter we wish to report what we believe to be a second example of the production and decay of an ^{–}, in this case the ^{–} decaying into a ^{o} and K^{–}. (Extracted from the introductory part of the paper.).

Accelerator
BNL
Detectors HBC-80IN

Related references More (earlier) information appears in V. E. Barnes et al., Phys. Rev. Lett. 12 (1964) 204;
See also M. Gell-Mann, Phys. Rev. 125 (1962) 1067;
S. Okubo, Progr. of Theor. Phys. 27 (1962) 949;
Y. Ne'eman, Nucl. Phys. 26 (1961) 222;
Analyse data from Y. Eisenberg, Phys. Rev. 96 (1954) 541;

Experiment comments
120000 pictures. Second event with characteristic ^{–} decay found.