Non-perturbative Renormalization of the Complete Basis of Four-fermion Operators and B-parameters

We present results on the B-parameters $B_K$, $B_7^{3\mathrm{/}2}$ and $B_8^{3\mathrm{/}2}$, at $\beta =6.0$, with the tree-level Clover action. The renormalization of the complete basis of dimension-six four-fermion operators has been performed non-perturbatively. Our results for $B_K$ and $B_7^{3\mathrm{/}2}$ are in reasonable agreement with those obtained with the (unimproved) Wilson action. This is not the case for $B_8^{3\mathrm{/}2}$. We also discuss some subtleties arising from a recently proposed modified definition of the B-parameters.