Clover Quark Action Research Articles

Light hadron spectrum and light quark masses from lattice QCD

We present recent results on the light hadron spectrum and light quark masses in lattice QCD, both in the quenched approximation and with two flavors of dynamical quarks. Simulations are made with a renormalization-group improved gauge action and a tadpole-improved clover quark action. Our new results in the quenched simulation are in good agreement with our previous calculation using the standard lattice action. A comparison between the results in full and quenched QCD clearly shows the existence of sea quark effects in meson and quark masses.

Quenched charmonium spectrum on anisotropic lattices

We present the results of quenched charmonium spectrum for S- and P-states, obtained by a relativistic heavy quark method on anisotropic lattices. Simulations are carried out using the standard plaquette gauge action and a meanfield-improved clover quark action at a −1 t = 3–6 GeV with the renormalized anisotropy fixed to ξ ≡ a s / a t = 3. We study the scaling of our fine and hyperfine mass splittings, and compare with previous results.

Full QCD light hadron spectrum and quark masses: Final results from CP-PACS

We present the final results of the CP-PACS calculation of the light hadron spectrum and quark masses with two flavors of dynamical quarks. Simulations are made with a renormalization-group improved gauge action and a mean-field improved clover quark action for sea quark masses corresponding to m PS/ m V ≈ 0.8-0.6 and the lattice spacing a = 0.22-0.11 fm. For the meson spectrum in the continuum limit a clearly improved agreement with experiment is observed compared to the quenched case, demonstrating the importance of sea quark effects. For light quark masses we obtain m MS ud (2 GeV) = 3.44 +0.14 0.22 MeV and m MS s (2 GeV) = 88 +4 −6 MeV ( K-input) and m MS s (2 GeV) = 90 +5 −11 MeV (φ-input), which are reduced by about 25% compared to the values in quenched QCD.

Light hadron spectrum and quark masses in QCD with two flavors of dynamical quarks

We present updated results of the CP-PACS calculation of the light hadron spectrum in N f = 2 full QCD. Simulations are made with an RG-improved gauge action and a tadpole-improved clover quark action for sea quark masses corresponding to m PS/ m V ≈ 0.8-0.6 and the lattice spacing a = 0.22-0.09 fm. A comparison of the N f = 2 QCD spectrum with new quenched results, obtained with the same improved action, shows clearly the existence of sea quark effects in vector meson masses. Results for light quark masses are also presented.

Equation of state in finite-temperature QCD with improved Wilson quarks

We study finite-temperature phase transition and equation of state for two-flavor QCD at N t = 4 using an RG-improved gauge action and a meanfield-improved clover quark action. The pressure is computed using the integral method. The O(4) scaling of chiral order parameter is also examined.

The static quark potential in full QCD

We report results on the static quark potential in two-flavor full QCD. The calculation is performed for three values of lattice spacing a −1 ≈ 0.9, 1.3 and 2.5 GeV on 12 3 × 24, 16 3 × 32 and 24 3 × 48 lattices respectively, at sea quark masses corresponding to m π/m ρ ≈ 0.8-0.6. An RG-improved gauge action and a tadpole-improved SW clover quark action are employed. We discuss scaling of ▪ and effects of dynamical quarks on the potential.

MILC studies of high temperature QCD — a progress report

We summarize recently completed studies of the equation of state for QCD with two flavors of Kogut-Susskind quarks on lattices with six time slices, and of the high temperature crossover for two flavors of Wilson quarks with a Symanzik improved gauge action and the clover quark action. In addition, we give a progress report on extensions of the Kogut-Susskind calculations at N t = 4 to smaller masses in an effort to clarify the scaling behavior near the transition.