BARYONS FROM QUARKS IN THE 1/N EXPANSION

We present a new formalism for treating baryons in the 1/N expansion, where N is the number of QCD colors, based on an analysis of quark-level diagrams. This method allows us to derive known results on the large-N limit in a very efficient and transparent manner: we show that there are an infinite number of degenerate baryon states in the large-N limit, and that forward matrix elements of quark bilinear operators satisfy the static quark-model relations. We also derive new results: we enumerate the corrections to the large-N relations to all orders in 1/N, and write an explicit effective lagrangian for baryon chiral perturbation theory which respects chiral symmetry to all orders in 1/N. These results give a simple algorithm to apply the 1/N expansion for baryons at N = 3. Finally, we compare our results for the corrections to the large-N relations to what is expected from a chiral constituent quark model.