Hadron Spectrum for Quenched Domain-Wall Fermions with DBW2 Gauge Action

Domain wall fermion (DWF)[1,2] is a promising tool to calculate hadronic quantities where chiral symmetry is important. Precise calculation of kaon mixing parameter BK is one success of this formulation[3]. More challenging calculations[4,5] of kaon weak matrix element for ′/ show a first reliable determination within lowest order chiral perturbation theory. Attempt to calculate nucleon matrix elements is also underway[6]. The good chiral property of DWF comes at an obvious cost, which is a substantial increase of computational effort associated with the size of the fifth dimension Ls. This makes taking the continuum limit by performing lattice finer than a−1 ' 2 GeV difficult. Going to a coarser lattice to have another point for the continuum extrapolation could be a better strategy. However, results[7,8] on coarser lattices show that an incredibly large size for the fifth dimension is required to keep the residual chiral symmetry breaking small. Motivated by the fact that improving the gauge action reduces the residual chiral symmetry breaking at finite Ls significantly at a−1 ' 2 GeV[7], we found the DBW2 action[9], which is a non-perturbatively determined Iwasaki-type action[10], gave much more improvement for the chiral properties[11,12]. Here we investigate basic physical quantities for the DBW2 gauge action for quenched DWF to see the viability of this approach down to a−1 ' 1.3 GeV.