Figure 1

Pion mass dependence of isovector axial charges. Stars denote physical inputs, while the points are lattice QCD results taken from 16, of which the value at the physical pion mass is obtained from an empirical quark-mass extrapolation, and the lowest mass data are used to estimate chiral limit couplings and local contributions at NLO. For $G_{\Lambda \Sigma }$ and $G_{\Sigma \Sigma }$, cusps appear at $m_{\pi }={\Delta }_{\Sigma \Lambda }$ where the $\Sigma$ becomes unstable to strong decay. Below this value, we plot the real part; the imaginary part is negative and an order of magnitude smaller.Reuse & Permissions