Kaon semileptonic decays near the physical point

Abstract

The CKM matrix element $|V_{us}|$ can be extracted from the experimental measurement of semileptonic $K\to \pi$ decays. The determination depends on theory input for the corresponding vector form factor in QCD. We present a preliminary update on our efforts to compute it in $N_f=2+1$ lattice QCD using domain wall fermions for several lattice spacings and with a lightest pion mass of about $170\mathrm{MeV}$. By using partially twisted boundary conditions we avoid systematic errors associated with an interpolation of the form factor in momentum-transfer, while simulated pion masses near the physical point reduce the systematic error due to the chiral extrapolation.

7 pages, 7 figures, Lattice 2012 PoS

References in corpus (2)

• Kl3 semileptonic form factor from 2+1 flavour lattice QCD
• K->pi form factors with reduced model dependence