Matrix elements of DI=3/2 K-->pi pi decays

TL;DR

This paper computes matrix elements for specific kaon decay processes using lattice QCD with Wilson fermions, employing chiral perturbation theory for physical extrapolation, focusing on electroweak penguins relevant to CP violation.

Contribution

It provides a numerical lattice calculation of DI=3/2 K to pi pi decay matrix elements, including electroweak penguin contributions at next-to-leading order.

Findings

Matrix elements computed at unphysical kinematics

Chiral perturbation theory used for extrapolation

Electroweak penguins O_{7,8} analyzed for epsilon'/epsilon

Abstract

We present a numerical computation of matrix elements of DI=3/2 K-->pi pi decays by using Wilson fermions. In order to extrapolate to the physical point we work at unphysical kinematics and we resort to Chiral Perturbation Theory at the next-to-leading order. In particular we explain the case of the electroweak penguins O_{7,8} which can contribute significantly in the theoretical prediction of epsilon'/epsilon. The study is done at beta=6.0 on a 24^3x64 lattice.