We compute the chiral corrections to octet baryon axial currents through ${ \cal O}(p^3)$ in heavy baryon chiral perturbation theory, including both octet and decuplet baryon intermediate states. We include the latter in a consistent way by using the small scale expansion. We find that, in contrast to the situation at ${ \cal O}(p^2)$, there exist no cancellations between octet and decuplet contributions at ${ \cal O}(p^3)$. Consequently, the ${ \cal O}(p^3)$ corrections spoil the expected scaling behavior of the chiral expansion. We discuss this result in terms of the $1/N_c$ expansion. We also consider the implications for determination of the strange quark contribution to the nucleon spin from polarized deep inelastic scattering data.
Categories: hep-ph