Sigma Hyperons Research Articles

Parity mixtures and decay processes

This paper examines the hypothesis that the mu meson as well as the LAMBDA and SIGMA hyperons are parity mixtures and shows that the facts commonly attributed to parity nonconservation are explained in a unified way by this hypothesis, provided physical theory is invariant with respect to parity conjugation. A simple theory of parity mixtures is developed in both parity conserving and parity destroying forms, to distinguish those experimental consequences which are incompatible with parity conservation. It is pointed out that the experiments on pi - mu -e decay do not establish a failure of parity conservation as claimed, and that there is at present no evidence which conclusively verifies the longitudinal neutrino hypothesis. The latter, however, may be regarded as an instance of a more general hypothesis that states of left- handed'' parity do not occur in nature, in favor of which prima facie evidence already exists. The facts concernlng the decay modes of the heavy mesons can also be explained readily on this basis. (auth)

Mass Differences of Σ+, Σ-and Σ0Hyperons

It is shown that there is a possibility to interpret the observed mass differences of SIGMA /sup +/, SIGMA /sup -/,and SIGMA /sup 0/ hyperons in terms of electromagnetic seif-energies, if the SIGMA hyperons are assumed to be Dirac particles with anomalous magnetic moments of a few nuclear magnetons.