Parity class, equivalence principle, and the mass formula for baryons and resonances

Abstract

Division of baryons and their resonances into two parity classes each governed by a unified mass formula in which the quantum number nu = J-1/2-Y (where J is the spin, Y the hypercharge) plays the role of mass number gives mass formulas completely specifying the mass spectra of the baryons and resonances. The formulas are based on an equivalence between an external quantum number J-1/2 and internal quantum number -Y that enter the mass number. The validity of the equivalence principle is demonstrated, and the accurate prediction of masses by the formulas is shown. (D.C.W.)