Speaker
Description
We summarize our results for the $\eta$ and $\eta^\prime$ masses and
their four independent decay constants at the physical point as well as
their anomalous gluonic matrix elements $a_{\eta^{(\prime)}}$.
The computation employs twenty-one $N_f=2+1$ Coordinated Lattice
Simulations (CLS) ensembles with non-perturbatively improved Wilson
fermions at four different lattice spacings and along two trajectories
in the quark mass plane, including one ensemble very close to physical
quark masses. We give details on the evaluation of the disconnected
contributions to the pseudoscalar and axialvector matrix elements. The
direct determination of both allows us to investigate the singlet PCAC
relation and to study the QCD scale dependence of the singlet currents.
