The role of the Roper resonance in n p --> d (pi pi)

Abstract

In this work, a model for the n p --> d (pi pi) reaction is developed. It is shown that the structure of the deuteron momentum spectra for a neutron beam momentum of 1.46 GeV can be explained as a consequence of the interplay of two mechanisms involving the excitation of the N^*(1440) resonance and its subsequent decay into N (pi pi)^{T=0}_{S-wave} and Delta pi respectively. The relevance of the present analysis for the study of the Roper excitation and decay properties, as well as for the interpretation of other two-pion production experiments is discussed.