Improving chiral property of domain-wall fermions by reweighting method

The reweighting method is applied to improve the chiral property of domain-wall fermions. One way to achieve this is to enlarge $L_s$, the size of fifth dimension, which controls the size of the induced chiral symmetry breaking. While this is a type of reweighting method for shifting the action parameter, it seems non-trivial since this reweighting means change of the five dimensional lattice volume. In this report, we address issues in this direction of reweighting and evaluate its effectiveness.Comment: 7 pages, talk presented at The XXVII International Symposium on Lattice Field Theory, July 26-31 2009, Peking University, Beijing, Chin

Lattice QCD with Domain-Wall Fermions

We study the quenched lattice QCD using domain-wall fermions at $\beta=6.0$. Behaviors of both pion mass and the explicit breaking term in the axial Ward-Takahashi identity support the existence of the chiral zero modes. We observe a good agreement between the pion decay constants $f_\pi$ from both the conserved axial current and the local current perturbatively renormalized at 1-loop. Finally the possible existence of the parity broken phase is also examined in this model.Comment: LATTICE99 (Chiral Fermions), 3 page

B_K from Two-flavor Dynamical Domain Wall Fermions

We report preliminary results from an ongoing calculation of $B_K$ for $N_f=2$ dynamical QCD with domain wall fermions. Simulations have been done with three dynamical quark masses on $16^3 \times 32$ volumes with $L_s = 12$, where the lattice spacing is $a^{-1} = 1.81(6)$ GeV. Using measurements on $\sim 70$ lattices for each dynamical mass and extrapolating \mdyn=\mval to the kaon point, we find $B_K^{\rm \bar{MS}}(\mu=2{\rm GeV}) = 0.503(20)$.Comment: Lattice2003(matrix), 3 pages, 2 figure

Lattice Gross-Neveu model with domain-wall fermions

We investigate the two-dimensional lattice Gross-Neveu model, using the domain-wall fermion formulation, as a toy model of lattice QCD. We study features of the phase diagram related to the mechanism of chiral symmetry restoration, and find that the parity-broken phase (Aoki phase) exists for finite extent in the extra dimension ($N_s$). We also find that O(a) scaling violation terms vanishes in the limit of $N_s\to\infty$.Comment: LATTICE99 (Chiral Fermions), 3 pages, 4 figure

Two-dimensional Lattice Gross-Neveu Model with Wilson Fermion Action at Finite Temperature and Chemical Potential

We investigate the phase structure of the two-dimensional lattice Gross-Neveu model formulated with the Wilson fermion action to leading order of 1/N expansion. Structural change of the parity-broken phase under the influence of finite temperature and chemical potential is studied. The connection between the lattice phase structure and the chiral phase transition of the continuum theory is clarified.Comment: 42 pages, 20 EPS figures, using REVTe

Double poles in Lattice QCD with mixed actions

We consider effects resulting from the use of different discretizations for the valence and the sea quarks, considering Wilson and/or Ginsparg--Wilson fermions. We assume that such effects appear through scaling violations that can be studied using effective-lagrangian techniques. We show that a double pole is present in flavor-neutral Goldstone meson propagators, even if the flavor non-diagonal Goldstone mesons made out of valence or sea quark have equal masses. We then consider some observables known to be anomalously sensitive to the presence of a double pole. We find that the double-pole enhanced scaling violations may turn out to be rather small in practice.Comment: 8 pages; combined writeup of talks given at Lattice 2005 (Dublin) and the Workshop on Computational Hadron Physics (Cyprus