Negative Parity 70-plet Baryon Masses in the 1/Nc Expansion
Abstract
The masses of the negative parity SU(6) 70-plet baryons are analyzed in the 1/Nc expansion to order 1/Nc and to first order in SU(3) breaking. At this level of precision there are twenty predictions. Among them there are the well known Gell-Mann Okubo and equal spacing relations, and four new relations involving SU(3) breaking splittings in different SU(3) multiplets. Although the breaking of SU(6) symmetry occurs at zeroth order in 1/Nc, it turns out to be small. The dominant source of the breaking is the hyperfine interaction which is of order 1/Nc. The spin-orbit interaction, of zeroth order in 1/Nc, is entirely fixed by the splitting between the singlet states Lambda(1405) and Lambda(1520), and the spin-orbit puzzle is solved by the presence of other zeroth order operators involving flavor exchange.
Keywords
Cite
@article{arxiv.hep-ph/0209174,
title = {Negative Parity 70-plet Baryon Masses in the 1/Nc Expansion},
author = {J. L. Goity and C. L. Schat and N. N. Scoccola},
journal= {arXiv preprint arXiv:hep-ph/0209174},
year = {2014}
}
Comments
31 pages, 3 figures