Masses of the 70- Baryons in large Nc QCD -: art. no. 102002

The masses of the negative parity 70-plet baryons are analyzed in large N-c QCD to order 1/Nc and to first order in SU(3) symmetry breaking. The existing experimental data are well reproduced and 20 new observables are predicted. The leading order SU(6) spin-flavor symmetry breaking is small and, as it occurs in the quark model, the subleading in 1/N-c hyperfine interaction is the dominant source of the breaking. It is found that the A(1405) and A(1520) are well described as three-quark states and spin-orbit partners. New relations between splittings in different SU(3) multiplets are found.