A Non-Standard Quark Model and the Mass Difference $Ξ^- - Ξ^0$

Abstract

We show that a highly unconventional theory, based on the 16 dimensional (${3\over2}$,${3\over2}$) irreducible representation of O(4), fits the masses of the baryons $Ξ^-$,$Ξ^0$,$Σ^-$,$Σ^0$,$Σ^+$,$Λ$,$p$,$n$ and the leptons $μ$,$e$,$ν_μ$,$ν_e$ to within current experimental error, yet yields a prediction substantially different from that of Coleman and Glashow, namely $Ξ^- - Ξ^0 < 6.1$ MeV. We discuss the ramifications of this very non-standard model in the hope to stimulate improved measurements of the $Ξ^- - Ξ^0$ mass difference.