$f_K/f_{π}$ from a combination of Wilson and Wilson twisted mass $N_f=2+1$ fermions

by Alejandro Saez Gonzalvo (Universitat de Valencia, IFIC)

Tuesday 2 Jun 2026, 16:00 → 18:00 Europe/Zurich

4/2-037 - TH meeting room (CERN)

We present results for $f_K/f_{π}$ with $N_f=2+1$ flavors, along with a determination of $|V_{us}|$ and a study on the unitarity of the first row of the Cabibbo-Kobayashi-Maskawa (CKM) matrix after introducing strong isospin-breaking and QED effects. The results obtained are based on a combination of a Wilson unitary action and a mixed action setup using Wilson twisted mass fermions in the valence, based on CLS ensembles. The combination of the two regularizations enables a more precise control over the continuum limit extrapolation, as both setups must share the same continuum limit, yet can exhibit distinct cutoff effects.

Alejandro Saez.pdf