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Negative Parity 70-plet Baryon Masses in the 1/Nc Expansion

J. L. Goity·C. L. Schat·N. N. Scoccola
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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.

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J. L. Goity, C. L. Schat, N. N. Scoccola. 2002-09-16. Negative Parity 70-plet Baryon Masses in the 1/Nc Expansion. https://doi.org/10.1103/physrevd.66.114014

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