ΔI = 1/2 rule and right-handed currents: Heavy-quark expansion and limitation on Zweig's rule

We reexamine and extend the analysis of the effects of right-handed currents on the ΔI = 1/2 rule in nonleptonic decays. The Wilson coefficients and anomalous dimensions of new operators generated by right-handed currents are computed. We apply the recently developed techniques of heavy-quark expansion to the resulting effective weak Hamiltonian. We point out that the short--distance enhanced operator (n/sub L/γ/sub μ/c/sub L/c-bar/sub R/γ/sup μ/lambda/sub R/) is expected to have large matrix elements, contrary to the naive implication of Zweig's rule. This may well account for the ΔI = 1/2 rule, if right-handed currents exist