Low-energy sum rules and large-Nc consistency conditions

The large-Nc consistency conditions for axial vector and isovector magnetic couplings of pions to baryons are discussed from the point of view of lowenergy current-algebra sum rules (Adler-Weisberger, Cabibbo-Radicati). In particular, we show how the result that ratios of axial vector and isovector magnetic coupling constants get corrections only at the order 1/N2 c follows from the Nc-counting of appropriate cross sections. This counting is performed using various approaches at the quark and hadronic level. Other implications of our method are also presented. ∗On leave of absence from Institute of Nuclear Physics, PL-31342 Cracow, Poland. E-mail: [email protected] †Alexander von Humboldt fellow 1