Two-loop mixing of dimension-five flavor-changing operators

Abstract

We calculate the two-loop QCD mixing of the dimension-five flavor-changing operators that arise in the Standard Model after integrating out the $W$, $Z$ and Higgs bosons and the top-quark, i.e.~the mixing among gluonic and photonic magnetic moment operators. Our calculation completes the two-loop anomalous dimension matrix of operators that govern low energy flavor-changing processes. It is an important ingredient of the next-to-leading calculation of the $B\to X_s\gamma$ decay rate.

Comments: (The only changes: We have removed a4wide.sty which worked only with the most recent version of Latex and added one referece), 16 pages (including figures), TUM-T31-79/94