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Inicio » Actividades I+D > Publicaciones 2002 > Negative Parity 70-Plet Baryon Masses in...
artículo con referato
"Negative Parity 70-Plet Baryon Masses in the 1/Nc Expansion"
J.L. Goity, C.L. Schat and N.N. Scoccola
Phys. Rev. D 66(11) (2002) 114014/1-15
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 ΛL(1405) and ΛL(1520), and the spin-orbit puzzle is solved by the presence of other zeroth order operators involving flavor exchange.
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