Baryon vector and axial-vector currents in the 1/N_c expansion
  The derivation of the 1/N_c expansions for the baryon vector and axial-vector currents, in the SU(3) symmetry limit and including perturbative SU(3) breaking, is reviewed. Symmetry breaking effects in the hyperon semileptonic decay form factors are reanalyzed. Fits to experimental data yield corrections to the leading vector and axial-vector form factors consistent with expectations. The values of the Cabibbo-Kobayashi-Maskawa matrix elements V_{ud} and V_{us} also extracted from the analysis are comparable to the ones recommended by the Particle Data Group. 
Raul Acosta, Ruben Flores-Mendieta