J. Noaki

Neutral-Kaon Mixing from (2 + 1)-Flavor Domain-Wall QCD

We present the first results for neutral-kaon mixing using (2+1)-flavors of domain-wall fermions. A new approach is used to extrapolate to the physical up and down quark masses from our numerical studies with pion masses in the range 240-420 MeV; only SU(2)_{L}xSU(2)_{R} chiral symmetry is assumed and the kaon is not assumed to be light. Our main result is B_{K};{MS[over ]}(2 GeV)=0.524(10)(28) where the first error is statistical and the second incorporates estimates for all systematic errors.

Two-flavor lattice QCD simulation in the epsilon-regime with exact chiral symmetry

We perform lattice simulations of two-flavor QCD using Neubergers overlap fermion, with which the exact chiral symmetry is realized at finite lattice spacings. The {epsilon} regime is reached by decreasing the light quark mass down to 3 MeV on a 16{sup 3}x32 lattice with a lattice spacing {approx}0.11 fm. We find a good agreement of the low-lying Dirac eigenvalue spectrum with the analytical predictions of the chiral random matrix theory, which reduces to the chiral perturbation theory in the {epsilon} regime. The chiral condensate is extracted as {sigma}{sup MS}(2 GeV)=(251{+-}7{+-}11 MeV){sup 3}, where the errors are statistical and an estimate of the higher order effects in the {epsilon} expansion.

Nonperturbative renormalization of quark bilinear operators and Bk using domain wall fermions

We present a calculation of the renormalization coefficients of the quark bilinear operators and the K-K mixing parameter B{sub K}. The coefficients relating the bare lattice operators to those in the RI/MOM scheme are computed nonperturbatively and then matched perturbatively to the MS scheme. The coefficients are calculated on the RBC/UKQCD 2+1 flavor dynamical lattice configurations. Specifically we use a 16{sup 3}x32 lattice volume, the Iwasaki gauge action at {beta}=2.13 and domain wall fermions with L{sub s}=16.

Polyakov loops and the Hosotani mechanism on the lattice

We explore the phase structure and symmetry breaking in four-dimensional SU(3) gauge theory with one spatial compact dimension on the lattice (

Topological susceptibility in two-flavor lattice QCD with exact chiral symmetry

16^3 \times 4

Lattice study of meson correlators in the epsilon-regime of two-flavor QCD

lattice) in the presence of fermions in the adjoint representation with periodic boundary conditions. We estimate numerically the density plots of the Polyakov loop eigenvalues phases, which reflect the location of minima of the effective potential in the Hosotani mechanism. We find strong indication that the four phases found on the lattice correspond to SU(3)-confined, SU(3)-deconfined, SU(2) x U(1), and U(1) x U(1) phases predicted by the one-loop perturbative calculation. The case with fermions in the fundamental representation with general boundary conditions, equivalent to the case of imaginary chemical potentials, is also found to support the

Chiral properties of domain wall quarks in quenched QCD.

Z_3

η′meson mass from topological charge density correlator in QCD

symmetry breaking in the effective potential analysis.

Chiral properties of light mesons with

Abstract We determine the topological susceptibility χ t in two-flavor QCD using the lattice simulations at a fixed topological sector. The topological charge density is unambiguously defined on the lattice using the overlap-Dirac operator which possesses exact chiral symmetry. Simulations are performed on a 16 3 × 32 lattice at lattice spacing ∼ 0.12 fm at six sea quark masses m q ranging in m s / 6 − m s with m s the physical strange quark mass. The χ t is extracted from the constant behavior of the time-correlation of flavor-singlet pseudo-scalar meson two-point function at large distances, which arises from the finite size effect due to the fixed topology. In the small m q regime, our result of χ t is proportional to m q as expected from chiral effective theory. Using the formula χ t = m q Σ / N f by Leutwyler–Smilga, we obtain the chiral condensate in N f = 2 QCD as Σ MS ¯ ( 2 GeV ) = [ 252 ( 5 ) ( 10 ) MeV ] 3 , in good agreement with our previous result obtained in the ϵ-regime.

N_f=2+1

We calculate mesonic two-point functions in the {epsilon}-regime of two-flavor QCD on the lattice with exact chiral symmetry. We use gauge configurations of size 16{sup 3}x32 at a{approx}0.11 fm generated with dynamical overlap fermions. The sea quark mass is fixed at around 3 MeV and the valence quark mass is varied in the range 1-4 MeV, both of which are in the {epsilon}-regime. We find a good consistency with the expectations from the next-to-leading order calculation in the {epsilon}-expansion of (partially quenched) chiral perturbation theory. From a fit we obtain the pion decay constant F=87.3(5.6) MeV and the chiral condensate {sigma}{sup MS}=[239.8(4.0) MeV]{sup 3} up to next-to-next-to-leading order contributions.