$F_K/F_\pi$ as a precision test of a new four flavor Domain Wall Fermion action
Renwick J. Hudspith, Nicolas Garron, Zack Hall, Andrew Hanlon, Henry Monge-Camacho, Colin Morningstar, Amy Nicholson, Dimitra A. Pefkou, Thomas R. Richardson, Fernando Romero-López, Miguel Salg, Wyatt A. Smith, Pavlos Vranas, André Walker-Loud, Bigeng Wang
We present a new set of lattice QCD ensembles with four flavors of smeared Möbius Domain Wall Fermions with good chiral symmetry and small fifth-dimensional extent. A modest amount of computing resources was sufficient to generate 30 publicly-available ensembles spanning five lattice spacings and a broad range of pion masses down to physical. To scrutinize our action we determine $F_{K^\pm}/F_{\pi^\pm}=1.1962(34)$, a key quantity for precision CKM unitarity tests, heralding a future of inexpensive high-precision calculations of hadronic observables with chiral fermions.