2 + 1 flavor domain wall QCD on a (2 fm)3 lattice : Light meson spectroscopy with Ls = 16

We present results for light meson masses and pseudoscalar decay constants from the first of a series of lattice calculations with 2 + 1 dynamical flavors of domain wall fermions and the Iwasaki gauge action. The work reported here was done at a fixed lattice spacing of about 0.12 fm on a 16 3 × 32 lattice, which amounts to a spatial volume of (2 fm) 3 in physical units. The number of sites in the fifth dimension is 16, which gives m res = 0.00308(4) in these simulations. Three values of input light sea quark masses, m sea l ≈ 0.85m s , 0.59m s and 0.33m s were used to allow for extrapolations to the physical light quark limit, while the heavier sea quark mass was fixed to approximately the physical strange quark mass m s . The exact rational hybrid Monte Carlo algorithm was used to evaluate the fractional powers of the fermion determinants in the ensemble generation. We have found that f π = 127(4) MeV, f K = 157(5) MeV and f K /f π = 1.24(2), where the errors are statistical only, which are in good agreement with the experimental values.