$|V_{us}|$ from kaon semileptonic form factor in $N_f = 2+1$ QCD at the physical point on (10 fm)$^4$

TL;DR

This paper reports a lattice QCD calculation of the kaon semileptonic form factor at the physical point, using large-volume configurations and multiple lattice spacings, to determine |V_{us}| with improved precision.

Contribution

It provides a new calculation of the kaon semileptonic form factor at the physical point on large volumes with multiple lattice spacings, advancing the precision of |V_{us}| determination.

Findings

Estimated |V_{us}| in the continuum limit.

Comparison with previous |V_{us}| results and leptonic decay methods.

Preliminary results at the smallest lattice spacing.

Abstract

We present a preliminary result of the kaon semileptonic form factor calculated at the smallest lattice spacing in the PACS10 configurations, whose physical volumes are more than (10 fm)$^4$ at the physical point. The configurations were generated using the Iwasaki gauge action and $N_f=2+1$ stout-smeared nonperturbatively $O(a)$ improved Wilson quark action at the three lattice spacings, 0.085, 0.063, and 0.041 fm. The value of $|V_{us}|$ in the continuum limit is estimated from our results including the preliminary one. We compare our result of $|V_{us}|$ with the previous results and those through the kaon leptonic decay.