Kaon semileptonic form factors in QCD with exact chiral symmetry

TL;DR

This paper presents a precise lattice QCD calculation of kaon semileptonic form factors using overlap quarks, enabling direct comparison with chiral perturbation theory and experimental data.

Contribution

It introduces a lattice QCD approach with exact chiral symmetry to accurately compute kaon form factors near zero momentum transfer.

Findings

Form factors are precisely calculated at multiple pion masses.

Results show good agreement with chiral perturbation theory.

Data aligns well with experimental measurements.

Abstract

We report on our calculation of the kaon semileptonic form factors in Nf=2+1 lattice QCD. Chiral symmetry is exactly preserved by using the overlap quark action for a straightforward comparison with chiral perturbation theory (ChPT). We simulate three pion masses down to 290 MeV at a single lattice spacing of 0.11 fm and at a strange quark mass very close to its physical value. The form factors near zero momentum transfer are precisely calculated by using the all-to-all propagator and twisted boundary conditions. We compare the normalizations and slopes of the form factors with ChPT and experiments.