Charmed meson spectra and decay constants with one-loop O(a)O(a) improved relativistic heavy quark action

We calculate charmed meson spectra and decay constants in lattice QCD employing one-loop $O(a)$ improved heavy quark action and axial-vector currents. In quenched simulations at $a \sim 0.1$ fm with the plaquette gauge action as well as a renormalization-group improved one, it is shown that the deviation from the continuum dispersion relation and the violation of space-time symmetry for the pseudoscalar meson decay constants are substantially reduced, once the $O(a)$ improvement is applied. Preliminary results with two flavors of dynamical quarks are also presented.Comment: 3 pages, 4 figure, talk presented at Lattice2004(heavy), Fermilab, June 21-26, 200

Light hadron spectroscopy with two flavors of O(a) improved dynamical quarks

We report on our study of light hadron spectrum and quark masses in QCD with two flavors of dynamical quarks. Simulations are made with the plaquette gauge action and the non-perturbatively $O(a)$ improved Wilson quark action. We simulate 5 sea qaurk masses corresponding to $m_{PS}/m_{V} \simeq 0.8$--0.6 at $\beta=5.2$ on $12^3 \times 48$, $16^3 \times 48$ and $20^3 \times 48$ lattices. A comparison with previous calculations in quenched QCD indicates sea quark effects in meson and quark masses

B meson decay constant from quenched Lattice QCD

A lattice QCD calculation of the B meson decay constant is presented. In order to investigate the scaling violation associated with the heavy quark, parallel simulations are carried out employing both Wilson and the O(a)-improved clover actions for the heavy quark. The discretization errors due to the large b quark mass are estimated in a systematic way with the aid of the non-relativistic interpretation approach of El-Khadra, Kronfeld and Mackenzie. As our best value from the quenched simulations at beta=5.9,6.1 and 6.3 we obtain fB=163±16 MeV and fBs=175±18 MeV in the continuum limit where the error includes both statistical and systematic uncertainties

Heavy-light matrix elements with the Wilson quark action

Status report is made of our quenched study of heavy-light matrix elements employing the Wilson quark action for heavy quark. Results obtained up to now with 200 configurations at β = 6.1 on a 243 × 64 lattice and with 100 configurations at β = 6.3 on a 323 × 80 lattice suggest that the pseudoscalar decay constant varies little over this range of β in both charm and bottom regions. Results for the B parameter are also reported

K+→π+π0 decay amplitude with the Wilson quark action in quenched lattice QCD

We present a calculation for the K+→π+π0 decay amplitude using a quenched simulation of lattice QCD with the Wilson quark action at β=6/g2=6.1. The decay amplitude is extracted from the ratio, the K→ππ three-point function divided by either K and π meson two-point functions or K meson two-point function and I=2 ππ four-point function; the two different methods yield consistent results. Finite size effects are examined with calculations made on 243×64 and 323×64 lattices, and are shown that they are explained by one-loop effects of chiral perturbation theory. The lattice amplitude is converted to the continuum value by employing a one-loop calculation of chiral perturbation theory, yielding a value in agreement with experiment if extrapolated to the chiral limit. We also report on the K meson B parameter BK obtained from the K+→π+π0 amplitude using chiral perturbation theory

K+ → π+π0 decay amplitude in quenched lattice QCD

A new study is reported of a lattice QCD calculation of the K+ → π+π0 decay amplitude with the Wilson quark action in the quenched approximation at β = 6.1. The amplitude is extracted from the K → ππ Green function, and a conversion to the continuum value is made employing a recent one-loop calculation of chiral perturbation theory. The result is consistent with the experimental value if extrapolated to the chiral limit

Heavy Meson Decay Constants from Quenched Lattice QCD

A quenched lattice QCD calculation of the B and D meson decay constants is presented. To investigate scaling violation associated with the heavy quarks, parallel simulations are carried out employing both Wilson and the O(a)-improved clover quark actions. The discretization errors due to the large b quark mass are estimated with the aid of the nonrelativistic interpretation approach of El-Khadra, Kronfeld, and Mackenzie [Phys. Rev. D 55, 3933 (1997)]. As the best values from our simulations at β = 5.9, 6.1, and 6.3 we obtain fB = 173(4) MeV, fBs = 1993 MeV for B mesons and fD = 1972 MeV, fDs = 2242 MeV for D mesons where the errors are statistical. In addition we expect a 5% ( 7-1.973389or D mesons) systematic error and a 5 6.880872e-316rror in the uncertainty to determine the lattice scale, besides the quenching error, which is not estimated in this Letter

Charmed meson spectra and decay constants with one-loop O(a) improved relativistic heavy quark action

We calculate charmed meson spectra and decay constants in lattice QCD employing one-loop O(a) improved heavy quark action and axial-vector currents. In quenched simulations at anot, vert, similar0.1 fm with the plaquette gauge action as well as a renormalization-group improved one, it is shown that the deviation from the continuum dispersion relation and the violation of space-time symmetry for the pseudoscalar meson decay constants are substantially reduced, once the O(a) improvement is applied. Preliminary results with two flavors of dynamical quarks are also presented

An exact Polynomial Hybrid Monte Carlo algorithm for dynamical Kogut-Susskind fermions

We present a polynomial Hybrid Monte Carlo (PHMC) algorithm as an exact simulation algorithm with dynamical Kogut-Susskind fermions. The algorithm uses a Hermitian polynomial approximation for the fractional power of the KS fermion matrix. The systematic error from the polynomial approximation is removed by the Kennedy-Kuti noisy Metropolis test so that the algorithm becomes exact at a finite molecular dynamics step size. We performed numerical tests withNf=2 case on several lattice sizes. We found that the PHMC algorithm works on a moderately large lattice of 16 4 atβ=5.7, m=0.02 (mps/mv≈0.69) with a reasonable computational time

A scaling study of the step scaling function of quenched QCD with improved gauge actions

We study the scaling behavior of the step scaling function for SU(3) gauge theory, employing the Iwasaki gauge action and the Luescher-Weisz gauge action. In particular, we test the choice of boundary counter terms and apply a perturbative procedure for removal of lattice artifacts for the simulation results in the extrapolation procedure. We confirm the universality of the step scaling functions at both weak and strong coupling regions. We also measure the low energy scale ratio with the Iwasaki action, and confirm its universality