Masses of the 70(-) baryons in large N(c) QCD.
The masses of the negative parity 70-plet baryons are analyzed in large N(c) QCD to order 1/N(c) 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 Lambda(1405) and Lambda(1520) are well described as three-quark states and spin-orbit partners. New relations between splittings in different SU(3) multiplets are found.
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Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606, USA.
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