Roper resonance and πN phase shift in the Skyrme model with defect

Abstract

The quantum fluctuations of the two-phase Skyrme soliton model of the nucleon is formulated. The p-wave πN phase shift and the Roper to πN decay width are calculated as a function of the equlibrium defect radius R 0. It is found that there is a preferred region of R 0 between 0.4 and 0.5 fm where the experimental width can be fitted. It is also found that the region of R 0 between 0.1 and 0.36 fm should be excluded in the model due to its instability against small oscillations.