On the number of pions in the topological soliton model with three quarks

Abstract

The classical soliton of the chiral invariant σ-model of Kahana, Ripka and Soni is re-interpreted as a coherent state. The corresponding number of pions in the nucleon is 1.2, almost independently of the parameters of the model. Projection of good angular momentum and isospin reduces the number of pions to about 0.7 and gives consistent values for nucleon mass, charge radius, the renormalized π NN coupling constant, magnetic moments and axial charge.