The Skyrmion strikes back: Baryons and a new large N_c limit

In the large N_c limit of QCD, baryons can be modeled as solitons, for instance, as Skyrmions. This modeling has been justified by Witten's demonstration that all properties of baryons and mesons scale with N_c^-1/2 in the same way as the analogous meson-based soliton model scales with a generic meson-meson coupling constant g. An alternative large N_c limit (the orientifold large N_c limit) has recently been proposed in which quarks transform in the two-index antisymmetric representation of SU(N_c). By carrying out the analog of Witten's analysis for the new orientifold large N_c limit, we show that baryons and solitons can also be identified in the orientifold large N _c limit. However, in the orientifold large N_c limit, the interaction amplitudes and matrix elements scale with N_c^-1 in the same way as soliton models scale with the generic meson coupling constant g rather than as N_c^-1/2 as in the traditional large N_c limit.