Baryons from quarks in the 1/N expansion

Oct, 1993
29 pages
Published in:
  • Nucl.Phys.B 426 (1994) 71-93
e-Print:
Report number:
  • LBL-34778

Citations per year

1993200120092017202402468101214
Abstract:
We present a diagrammatic analysis of baryons in the 1/N1/N expansion, where NN is the number of QCD colors. We use this method to show that there are an infinite number of degenerate baryon states in the large-NN limit. We also show that some (but not all) forward matrix elements of local operators satisfy the static quark-model relations in this limit. We enumerate the corrections to these relations to all orders in 1/N1/N for baryon masses and for matrix elements of quark bilinear operators. (The method can be extended to arbitrary operators.) Our results imply that the quark-model relations for the axial currents and magnetic moments get corrections of order 1/N 21/N~2, while the quark-model relations for baryon mass differences due to current quark masses are not satisfied in the large-NN limit. We also discuss how these results fit into the framework of baryon chiral perturbation theory, and compare our results to what is expected from a chiral constituent quark model.
  • quantum chromodynamics
  • operator: local
  • quark: nonrelativistic
  • baryon: mass
  • mass: baryon
  • current: axial
  • magnetic moment
  • perturbation theory: chiral
  • expansion 1/N