Quadrupole Moments of N and Delta in the 1/N_c Expansion
  We calculate expressions for the quadrupole moments of nonstrange baryons in which the number of QCD color charges is N_c. Using only the assumption of single-photon exchange, we obtain 4 relations among the 6 moments, and show how all of them may be obtained from Q_{\Delta^+ p} up to O(1/N_c^2) corrections. We compare to the N_c=3 case, and obtain relations between the neutron charge radius and quadrupole moments. We also discuss prospects for the measurement of these moments. 
Alfons J. Buchmann, Janice A. Hester, Richard F. Lebed