Chiral loop corrections and isospin violation effects in ɛ'/ɛ

Abstract

A complete analysis of isospin breaking in K → 2π amplitudes, including both strong (mu = m d ) and electromagnetic corrections at next-to-leading order in chiral perturbation theory, has been achieved recently [1]. We discuss the implication of these effects [2], together with the previously known chiral loop corrections [3,4], on the direct CP-violating ratio ε ′ /ε.