Anomalous dimensions of four-quark operators in the large N_f limit
Abstract
Description
The anomalous dimensions of four-quark operators $(\bar q_i q_j)_{V-A} (\bar q_k q_l)_{V-A}$ are calculated in the large $N_f$ limit. As expected, the result is a convergent series without renormalon ambiguities. Using the approximation of "Naive Nonabelianization", an additional all-order contribution to the anomalous dimension matrix is obtained which is somewhat larger than the exact NLO correction itself. Possible phenomenological applications in nonleptonic B decays and $B^0 - \bar B^0$ mixing are briefly considered.
17 pages, LaTex, two figures
17 pages, LaTex, two figures