Lowest negative parity baryons in the $1/N_c$ expansion

Abstract

We review a recently proposed approach to study the lowest negative parity baryons within the $1/N_c$ expansion. The method is based on the derivation of the matrix elements of SU(2N$_f$) generators for mixed symmetric $[N_c-1,1]$ flavor-spin states. Presently it is applied to the N = 1 band and a comparison is made with a former method based on the decoupling of the system into a symmetric core of $N_c-1$ quarks and an excited one. We prove that the decoupling is not necessary and moreover, it misses some important physical consequences.

Prepared for the Proceedings of the EMMI Workshop and Max-Born Symposium, Wroclaw, July 9-11, 2009, 8 pages, 5 tables