Non-perturbative Renormalization of Four-Fermion Operators Relevant to   $B_K$ with Staggered Quarks
  We present preliminary results of matching factors of the four-fermion operators relevant to $B_K$, which are obtained using the non-perturbative renormalization (NPR) method in the RI-MOM scheme with HYP-smeared improved staggered fermions. We use the MILC asqtad coarse ($a \cong 0.12\,$fm) ensembles with $20^3 \times 64$ geometry and $am_{\ell}/am_s = 0.01/0.05$. We compare NPR results with those of one-loop perturbative matching. 
Hwancheol Jeong, Jangho Kim, Jongjeong Kim, Weonjong Lee, Jeonghwan   Pak, Sungwoo Park
hep-lat