$f_K/f_{\ddot{I}}€$ in iso-symmetric QCD and the CKM matrix unitarity

Alessandro Conigli, Julien Frison, Alejandro Sáez

We present lattice results for $f_K/f_{\ddot{I}}€$ in the iso-symmetric limit of pure QCD (isoQCD) with $N_f=2+1$ flavours, along with a determination of $|V_{us}|/|V_{ud}|$ and a study on…