Lattice B-parameters for $\Delta S=2$ and $\Delta I=3/2$ Operators

Abstract

We compute several matrix elements of dimension-six four-fermion operators and extract their B-parameters. The calculations have been performed with the tree-level Clover action at $\beta =6.0$. The renormalization constants and mixing coefficients of the lattice operators have been obtained non-perturbatively. In the $\text{MSbar}$ renormalization scheme, at a renormalization scale $\mu \simeq 2$ GeV, we find $B_K(B_9^{3/2})=0.66(11),B_7^{3/2}=0.72(5)$ and $B_8^{3/2}=1.03(3)$. The result for $B_8^{3/2}$ has important implications for the calculation of ${ϵ}^{\prime }/ϵ$.

Comments: LaTeX, 14 pages, revised version (sign misprint in eq. (21) corrected)