Isospin-violating contributions to ∈′/∈
V. Cirigliano, H. Gisbert, A. Pich, A. Rodríguez-Sánchez
Abstract
A bstract 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 /N C -suppressed contributions to some relevant chiral-perturbation-theory low-energy constants.
Topics & Concepts
PhysicsCurrent (fluid)Standard Model (mathematical formulation)Particle physicsTheoretical physicsIgnoranceQuarkStatistical physicsTop quarkPhysics beyond the Standard ModelCP violationQuantum electrodynamicsLimit (mathematics)Neutral currentParticle physics theoretical and experimental studiesQuantum Chromodynamics and Particle InteractionsBlack Holes and Theoretical Physics