Isospin-violating contributions to ∈^′/∈

TY - JOUR

T1 - Isospin-violating contributions to ∈′/∈

AU - Cirigliano, V.

AU - Gisbert, H.

AU - Pich, A.

AU - Rodríguez-Sánchez, A.

PY - 2020/2/1

Y1 - 2020/2/1

N2 - The known isospin-breaking contributions to the K → ππ amplitudes 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.

AB - The known isospin-breaking contributions to the K → ππ amplitudes 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.

KW - Chiral Lagrangians

KW - CP violation

KW - Effective Field Theories

KW - Kaon Physics

U2 - 10.1007/JHEP02(2020)032

DO - 10.1007/JHEP02(2020)032

M3 - Article

AN - SCOPUS:85079421177

VL - 2020

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

SN - 1029-8479

IS - 2

M1 - 32

ER -