Speaker
Description
We review the status of a new analysis by the Fermilab Lattice and MILC collaborations towards a correlated determination of SU(3) Chiral Perturbation Theory (ChPT) low-energy constants (LECs). The analysis is based on chiral-continuum fits to light-meson mass and decay constant data generated using highly improved staggered quarks (HISQ) on the $N_f=2+1+1$ MILC HISQ ensembles. Our fitting strategy combines staggered ChPT (SChPT) at NLO with continuum ChPT at NNLO. Since SU(3) ChPT converges poorly at the physical strange quark mass, we restrict this study to ensembles with lighter-than-physical strange quark masses, spanning three lattice spacings. We will discuss the potential of our fits to determine the different LO and NLO ChPT LECs, as well as the strategy to estimate systematic errors.