The Role of the Roper in QCD

Abstract

We show that existing data suggest a simple scenario in which the nucleon, and the Delta and Roper resonances act as chiral partners in a reducible representation of the full QCD chiral symmetry group. We discuss the peculiar interpretation of this scenario using spin-flavor symmetries of the naive constituent quark model, as well as the consistency of the scenario with large-Nc expectations.

Comments: 16 pages TeX, uses mtexsis.tex