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Nucleon description in a projected chiral soliton model with dynamical confinement

Authors: T. Neuber, M. Fiolhais, K. Goeke and J.N. Urbano

Ref.: Nuclear Physics A 560, 909-944 (1993)

Abstract: We present a nucleon description based on a chiral version of a colour-dielectric model with non-strange quarks and scalar-isoscalar (sigma) and pseudoscalar-isovector (pi over arrow pointing right) meson fields. Approximate solutions of the model are obtained in a beyond-mean-field calculation. Quarks are treated in the valence approximation, occupying the same nodeless s-orbit. Coherent states are used to describe the meson clouds. The total baryon state has a hedgehog shape. A standard projection formalism is used to obtain model states with definite angular momentum and isospin and total linear momentum zero. To a large extent we use a variation-after-projection (VAP) procedure to obtain radial amplitudes for the mesons and quarks. The model state which describes the nucleon is used for evaluating its static properties. The projection on linear momentum causes a major effect on the rest mass of the nucleon. This effect amounts to approximately 30% decrease with respect to the mean-field energy. Except for the charge radius of the proton, the other observables are less affected by the projections. We find sets of parameters for which a reasonable nucleon description is obtained.