Zur Theorie der „seltsamen“ Teilchen

Abstract

The strange particles can be represented within the framework of the nonlinear spinor theory by taking into account the degeneracy with respect to isospin and parity of the groundstate “vacuum”. Use is made of the mathematical analogy between the theory of superconductivity and the theory of elementary particles, and in a first approximation a fourfold degeneracy of the ground-state is assumed. Each auf the four states is considered as a mixture of states of similar symmetry. The Green-functions of the type $\left\langle {{\Omega_{\alpha }}\left| {TX(x)\bar{X}\left( {x'} \right)} \right|{\Omega_{\beta }}} \right\rangle$ are considered as invariant under the proper Lorentz-group, CPT and PG, applied on the field operators or the states $\left. {{\Omega_{\alpha }}} \right\rangle$ separately; but as invariant under isospin rotation, P or CT or G, only if the transformation is applied on the field-operators and the states $\left. {{\Omega_{\alpha }}} \right\rangle$ simultaneously. Parity is represented in a manner discussed in an earlier paper by one of the authors. Only stationary states of strangeness 1 can be considered in this approximation. The fourfold degeneracy of the K-meson is reduced to an additional symmetry which may be connected later with the existence of electromagnetic charge. The results of the calculations may be interpreted by describing the strange particles as composed of ordinary particles and a “spurion” taken from the groundstate “vacuum”. The “spurion” carries an isospin 1/2 and a parity. The masseigenvalues and the parity of the particles are calculated by means of a slightly improved version of the Tamm-Dancoff-method. The theoretical masseigenvalues agree qualitatively with the observed masses. The calculated relative parities of the strange particles may later be checked by experiments. Besides the known particles of strangeness 1, the theory yields other eigen-states which are probably highly unstable since they could disintegrate into more stable particles by means of strong or electromagnetic interactions.