Hyperon couplings from $N_f=2+1$ lattice QCD

We compute various (generalized) isovector charges of the octet baryons. These include $g_A$, $g_T$ and $g_S$ as well as the unpolarized, polarized and transversity parton distribution function (PDF) momentum fractions $\langle x\rangle_{u^±d^+}$,$\langle x\rangle_{\Delta u^–\Delta d^-}$and$\langle x\rangle_{\delta u^±\delta ^+}$. The simulations are carried out on a subset of the (isospin symmetric) $N_f=2+1$ flavour Coordinated Lattice Simulations (CLS) gauge ensembles with lattice spacings ranging from $a\approx 0.086$fm down to $a\approx 0.050$fm. First results on the breaking of flavour symmetry and the low energy constants $F$ and $D$ are presented. While SU(3) flavour symmetry violations are found to be sizeable for $g_A=\langle 1\rangle_{\Delta u^±\Delta d^+}$,thesearequitesmallfor$g_T=\langle 1\rangle_{\delta u^–\delta d^-}$and$\langle x\rangle_{u^±d^+}$.