Isospin-violating contributions to ∈′/∈

• DOI: 10.1007/jhep02(2020)032
• Publication Date: 2020-02-13T06:41:16Z
• Authors: V. Cirigliano; H. Gisbert; A. Pich; A. Rodríguez-Sánchez
• Keywords: High Energy Physics - Lattice (hep-lat); FOS: Physical sciences; Effective Field Theories; QC770-798; 01 natural sciences; High Energy Physics - Experiment; Kaon Physics; High Energy Physics - Phenomenology; High Energy Physics - Experiment (hep-ex); CP violation; High Energy Physics - Lattice; High Energy Physics - Phenomenology (hep-ph); Nuclear and particle physics. Atomic energy. Radioactivity; Chiral Lagrangians; 0103 physical sciences

AbstractThe known isospin-breaking contributions to theK → ππamplitudes are reanalyzed, taking into account our current understanding of the quark masses and the relevant non-perturbative inputs. We present a complete numerical reappraisal of the direct CP-violating ratio ∈′/∈, where these corrections play a quite significant role. We obtain the Standard Model prediction Re (∈′/∈) = (14±5)·10−4, which is in very good agreement with the measured ratio. The uncertainty, which has been estimated conservatively, is dominated by our current ignorance about 1/NC-suppressed contributions to some relevant chiral-perturbation-theory low-energy constants.