Chiral extrapolation and finite-volume dependence of the hyperon vector couplings

Abstract

The hyperon vector form factors at zero momentum transfer, $f_1(0)$, play an important role in a precise determination of the Cabibbo-Kobayashi-Maskawa matrix element $V_{us}$. Recent studies based on lattice chromodynamics (LQCD) simulations and covariant baryon chiral perturbation theory yield contradicting results. In this work, we study chiral extrapolation of and finite-volume corrections to the latest $n_f=2+1$ LQCD simulations. Our results show that finite-volume corrections are relatively small and can be safely ignored at the present LQCD setup of $m_{\pi }L=4.6$ but chiral extrapolation needs to be performed more carefully. Nevertheless, the discrepancy remains and further studies are needed to fully understand it.

Comments: 21 pages, 4 figures