Baryon resonances at large Nc, or Quark Nuclear Physics

Abstract

We suggest a new point of view according to which baryon resonances can be understood as collective excitations about intrinsic one-quark excitations in a mean field of definite symmetry. This approach is justified in the limit of large number of colours Nc, and is similar to the physics of large-A nuclei, hence "quark nuclear physics". Although in the real world Nc is only three, we obtain a good agreement with the observed resonance spectrum of light baryons up to 2 GeV, and of lowest charmed baryon multiplets. A by-product of the scheme is the prediction of new exotic charmed (and bottom) baryons that may be stable against strong decays.

Comments: Invited talk at the Sixth International Conference on Quarks and Nuclear Physics, April 16-20, 2012, Ecole Polytechnique, Palaiseau, Paris, France, to be published in the Proceedings