Expansion of QCD
نویسندگان
چکیده
We identify “spurious” states in meson-baryon scattering, those that appear in QCD for Nc > 3 but decouple for Nc = 3. The key observation is that the relevant flavor SU(3) Clebsch-Gordan coefficients contain factors of 1−3/Nc. We show that this method works even if SU(3) is badly broken. We also observe that resonant scattering poles lying outside naive quark model multiplets are not necessarily large Nc artifacts, and can survive via configuration mixing at Nc=3.
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