Towards NNLO accuracy for ε'/ε

Tuesday, 12 November 2019 at 11:15, in Y16 G05 - Campus Irchel

Novel lattice results reveal a tension between the measured direct CP violation in 𝐾→𝜋𝜋 decays and the standard model theory prediction, with the theoretical uncertainty dominating. This inconsistency could have several sources, one of which could be the missing contribution of new particles in the theory predictions. However, a reliable standard model prediction is needed to disentangle possible new physics effects from the standard model background. As rapid progress on the lattice is bringing non-perturbative long-distance effects under control, a more precise knowledge of short-distance contributions is essential. We describe the first NNLO calculation for this observable and discuss future prospects, as well as issues of scheme dependence and the separation of perturbative and non-perturbative effects.