# The 39th International Symposium on Lattice Field Theory (Lattice 2022)

Aug 8 – 13, 2022
Hörsaalzentrum Poppelsdorf
Europe/Berlin timezone

## $f_K$ and $f_\pi$ from staggered QCD

Aug 10, 2022, 3:00 PM
20m
CP1-HSZ/Ground-0.002 - HS4 (CP1-HSZ)

### CP1-HSZ/Ground-0.002 - HS4

#### CP1-HSZ

50
Oral Presentation Standard Model Parameters

### Speaker

Finn Stokes (Forschungszentrum Jülich)

### Description

The decay constants of the kaon and pion provide important input into the determination of light CKM matrix elements. Here we present current progress in computing these quantities using the ensembles and analysis techniques employed by the Budapest-Marseille-Wuppertal collaboration in our recent determination of $a_{\mu}^{LO,HVP}$. This work will provide input on the current 2.6-sigma tension between lattice-based determinations and CKM unitarity. It also serves as a cross-check of the many aspects of the analysis shared with our $a_{\mu}^{LO,HVP}$ determination. While this analysis includes considerably more statistics than previous lattice calculations, the total errors on the ratio $f_K/f_\pi$ are similar to the best existing determinations. This is a result of our comprehensive and conservative approach to systematic error estimation, which was developed for $a_{\mu}^{LO,HVP}$.

### Primary author

Finn Stokes (Forschungszentrum Jülich)