Martin Gorbahn [HET Seminar] Matching calculations for semi-leptonic decays and epsilon_K

Thursday 30 Oct 2025, 11:00 → 13:00 US/Eastern

Small Seminar Room

Precision flavour observables, such as CKM unitarity tests and CP violation in meson mixing, provide stringent constraints on physics beyond the Standard Model. Achieving the required theoretical precision to match experimental accuracy necessitates high-order perturbative calculations and their combination with Lattice QCD results. In this talk, I will present the necessary QED  x QCD calculations for semi-leptonic decays and discuss the NNLO prediction of epsilon_K. A particular focus will be on two-loop lattice matching calculations. Here, I will first discuss momentum subtraction schemes and their implementation in the continuum and the lattice. Special care is given to the application of Ward Identities at these off-shell momentum subtraction points for semi-leptonic decays. Finally, the impact on CKM unitarity tests and the non-perturbative parameter B_K, relevant for K mixing, is derived.

 

https://bnl.zoomgov.com/j/16010362754?pwd=Z1l1SS9JUDlyR1hSUHNyaDV1dTZHUT09 

gorbahn_10_30_25.pdf