Photo-production of Positive Parity Excited Baryons in the 1/Nc Expansion of QCD
We analyze the photo-production helicity amplitudes for the positive parity excited baryons in the context of the $1/N_c$ expansion of QCD. The results show that sub-leading corrections in $1/N_c$ are important and that, while 1-body effective operators are dominant, there is some evidence for the need of 2-body effects.