Decays of nonstrange negative parity baryons in the 1/Nc expansion

Abstract

The decays of nonstrange negative parity baryons via the emission of single π and η mesons are analyzed in the framework of the 1/Nc expansion. A basis of spin-flavor operators for the partial wave amplitudes is established to order 1/Nc and the unknown effective coefficients are determined by fitting to the S- and D-wave partial widths as provided by the Particle Data Group. A set of relations between widths that result at the leading order, i.e., order Nc0, is given and tested with the available data. The rather large errors of the input partial widths, that result from the often discrepant results for the resonance parameters from different analyses of the data, lead to a rather good fit at the leading order Nc0. The next to leading order fit fails for the same reason to pin down with satisfactory accuracy the subleading effective coefficients. The hierarchy expected from the 1/Nc expansion is however reflected in the results. © 2005 The American Physical Society.