Extraction of K → ππ matrix elements with Wilson fermions

We present the status of a lattice calculation for the K → ππ matrix elements of the ΔS = 1 effective weak Hamiltonian, directly with two pion in the final state. We study the energy shift of two pion in a finite volume both in the I = 0 and I = 2 channels. We explain a method to avoid the Goldstone pole contamination in the computation of renormalization constants for ΔI=32 operators. Finally we show some preliminary results for the matrix elements of ΔI=12 operators. Our quenched simulation is done at β=6.0, on a 243 × 64 lattice.