[70,l+] baryons in large Nc QCD revisited: The effect on Regge trajectories

A simple procedure within the 1/N_c expansion method where all the N_c
quarks are treated on the same footing has been found successful in describing mixed symmetric negative parity baryon states belonging to the [{\bf 70},\ell^-] multiplets of the N = 1 and 3 bands. Presently it is applied to mixed symmetric positive parity [{\bf 70},0^+] and [{\bf 70},2^+] multiplets of the N = 2 band. We search for the most dominant terms in the mass formula. The results are compared to those obtained in the procedure where the system is separated into a core and an excited quark. We find that both the spin and isospin operators of the entire system of N_c quarks play dominant roles in describing the data, like for negative parity states. As a by-product we present the contribution of the leading spin-isospin singlet term as a function of the band number, which hints at distinct Regge trajectories for the symmetric and mixed symmetric states.