The deconfining finite-temperature transition of SU(3) gauge theory is studied on the dedicated parallel computer QCDPAX. Monte Carlo simulations are performed on 12* x 24X 4, 242 x 36 x 4, 203 X 6, 243 X 6, and 362 X 48 X 6 lattices with 376 000 to 1 112 000 iterations. The finite size scaling behavior of the first-order transition is confirmed both on the N,=4 and N, =6 lattices and clear two-phase structures are observed on spatially large lattices ( 2 4 2~3 6 X 4 and 3 6 2~4 8~6 ) .The latent heat at the deconfining transition is estimated both by a direct measurement of the gap on the spatially large lattices and by applying a finite-size scaling law. The results obtained by these two independent methods are remarkably consistent with each other on both the N, =4 and 6 lattices. The latent heat for N, = 6 is much smaller than that for N, =4 and is about f of the Stefan-Boltzmann value 8p2/15. The details of the data and the error analysis are presented.PACS number(s): 11.15. Ha, 12.38.Gc, 12.38.Mh

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We present results of a numerical calculation of lattice QCD with two degenerate flavors of dynamical quarks, identified with up and down quarks, and with a strange quark treated in the quenched approximation. The lattice action and simulation parameters are chosen with a view to carrying out an extrapolation to the continuum limit as well as chiral extrapolations in dynamical up and down quark masses. Gauge configurations are generated with a renormalization-group improved gauge action and a mean field improved clover quark action at three values of β = 6/g 2 , corresponding to lattice spacings of a ≈ 0.22, 0.16 and 0.11 fm, and four sea quark masses corresponding to mPS/mV ≈ 0.8, 0.75, 0.7 and 0.6. The sizes of lattice are chosen to be 12 3 × 24, 16 3 × 32 and 243 × 48 so that the physical spatial size is kept constant at La ≈ 2.5 fm. Hadron masses, light quark masses and meson decay constants are measured at five valence quark masses corresponding to mPS/mV ≈ 0.8, 0.75, 0.7, 0.6 and 0.5. We also carry out complementary quenched simulations with the same improved actions. The quenched spectrum from this analysis agrees well in the continuum limit with the one of our earlier work using the standard action, quantitatively confirming the systematic deviation of the quenched spectrum from experiment. We find the twoflavor full QCD meson masses in the continuum limit to be much closer to experimental meson masses than those from quenched QCD. When using the K meson mass to fix the strange quark mass, the difference between quenched QCD and experiment of 2.6 −0.031 in two-flavor full QCD, approaching the experimental value J ≈ 0.48. We take these results as manifestations of sea quark effects in two-flavor full QCD. For baryon masses full QCD values for strange baryons such as Ξ and Ω are in agreement with experiment, while they differ increasingly with decreasing strange quark content, resulting in a nucleon mass higher than experiment by 10% and a ∆ mass by 13%. The pattern suggests finite size effects as a possible origin for this deviation. For light quark masses in the continuum limit we obtain m −11 MeV (φ-input), which are reduced by about 25% compared to the values in quenched QCD. We also present results for decay constants where large scaling violations obstruct a continuum extrapolation. Need for a non-perturbative estimate of renormalization factors is discussed.

The CP-PACS computer with a peak speed of 300 Gflops was completed in March 1996 and has started to operate. We describe the final specification and the hardware implementation of the CP-PACS computer, and its performance for QCD codes. A plan of the grade-up of the computer scheduled for fall of 1996 is also given.