Momentum transfer dependence of kaon semileptonic form factor on (10 fm)$^4$ at the physical point

TL;DR

This study computes kaon semileptonic form factors on large physical-volume lattices at the physical point, analyzing momentum transfer dependence to extract key parameters and determine the CKM matrix element |V_{us}|, comparing with prior results.

Contribution

First lattice calculation of kaon semileptonic form factors on large (10 fm)^4 volumes at the physical point with multiple lattice spacings, providing precise momentum transfer dependence.

Findings

Determined slope and curvature of form factors at zero momentum transfer.

Calculated phase space factor to extract |V_{us}|.

Results consistent with previous lattice and experimental data.

Abstract

We calculate the kaon semileptonic form factors using the two sets of the PACS10 configuration, whose physical volumes are more than (10 fm)$^4$ at the physical point. The lattice spacings are 0.063 and 0.085 fm. The configurations were generated using the Iwasaki gauge action and $N_f=2+1$ stout-smeared nonperturbatively $O(a)$-improved Wilson quark action. From the momentum transfer dependence of the form factors, we evaluate the slope and curvature for the form factors at the zero momentum transfer. Furthermore, we calculate the phase space factor, which is used to obtain $|V_{us}|$ through the kaon semileptonic decay. These results are compared with previous lattice results and experimental values.