SM wilson coefficients at the charm scale
To calculate the standard model wilson coefficients for rare charm decays, a two step matching procedure is used: First, the Higgs-, $W^\pm$- and $Z$-boson, as well as the $t$-quark, are integrated out and a matching is performed at the $W$-scale $m_W$. Then the EFT can be evolved down to $m_b$ where the $b$-quark is integrated out and the coefficients are matched again.