Comment on the Walliser-Weigel approach to exotic baryons in chiral soliton models

Abstract

This comment discusses a recent paper by Walliser and Weigel on the quantization of chiral soliton models in the context of exotic baryons. Claims made in that work are misleading due to unfortunate nomenclature. Moreover, attempts in that paper to go beyond the leading order calculations of the phase shifts are ad hoc and never justified. This comment also addresses a technical issue in that paper: the identification of the excitation energy of the pentaquark obtained via conventional rigid rotor quantization with a frequency obtained in the context of small amplitude fluctuations. The identification is erroneous: the small amplitude fluctuation result is based on a first-order perturbation computation of the frequency around a zero mode solution at a frequency far from zero and well away from the perturbative regime.