PT Journal
AU Cirigliano, V
   Gisbert, H
   Pich, A
   Rodriguez-Sanchez, A
TI Isospin-violating contributions to epsilon '/epsilon
SO Journal of High Energy Physics
JI J. High Energy Phys.
PY 2020
BP 032
EP 44pp
VL 02
IS 2
DI 10.1007/JHEP02(2020)032
LA English
DE Chiral Lagrangians; CP violation; Effective Field Theories; Kaon Physics
AB The known isospin-breaking contributions to the K -> pi pi 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 is an element of(')/is an element of, where these corrections play a quite significant role. We obtain the Standard Model prediction Re (is an element of(')/is an element of) = (14 +/- 5) <bold> </bold>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/N-C-suppressed contributions to some relevant chiral-perturbation-theory low-energy constants.
ER