Tue·Oct 23, 2001Tuesday·October 23, 2001

1. 01*

   Phenomenological Models of the Quark-Gluon Plasma Equation of State

   Peter N. Meisinger🇺🇸 · Travis R. Miller🇺🇸 · Michael C. Ogilvie🇺🇸

   Two phenomenological models describing an SU(N) quark-gluon plasma are presented. The first is obtained from high temperature expansions of the free energy of a massive gluon, while the second is derived by demanding color neutrality over a certain length scale. Each model has a single free parameter, exhibits behavior similar to lattice simulations over the range T_d-5T_d, and has the correct blackbody behavior for large temperatures. The N=2 deconfinement transition is second order in both models, while N=3,4, and 5 are first order. Both modelsappear to have a smooth large-N limit. In both models, the confined phase is characterized by a mutual repulsion of Polyakov loop eigenvalues that makes the Polyakov loop expectation value zero. In the deconfined phase, the rotation of the eigenvalues in the complex plane towards 1 is responsible for the approach to the blackbody limit over the range T_d-5T_d. The addition of quarks in SU(3) breaks Z(3) symmetry weakly and eliminates the deconfining phase transition for sufficiently light quarks.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·0 citations
2. 02*

   Phenomenological Equations of State for SU(N) Gauge Theories

   Peter N. Meisinger🇺🇸 · Travis R. Miller🇺🇸 · Michael C. Ogilvie🇺🇸

   Two phenomenological models describing an SU(N) gluon plasma are presented using the eigenvalues of the Polyakov loop as the order parameters of the deconfinement transition. Each model has a single free parameter and exhibits behavior similar to lattice simulations over the range T_d-5T_d. The N=2 deconfinement transition is second order in both models, while N=3,4, and 5 are first order. Both models appear to have a smooth large-N limit. The confined phase is characterized by a mutual repulsion of Polyakov loop eigenvalues that makes the Polyakov loop expectation value zero. The motion of the eigenvalues is responsible for the approach to the blackbody limit over the range T_d-5T_d.

   hep-lat1 citation
3. 03*

   Constrained Curve Fitting

   G.P. Lepage🇺🇸 · B. Clark🇺🇸 · C.T.H. Davies🇬🇧 · K. Hornbostel🇺🇸 · P.B. Mackenzie🇺🇸 · C. Morningstar🇺🇸 · H. Trottier🇨🇦

   We survey techniques for constrained curve fitting, based upon Bayesian statistics, that offer significant advantages over conventional techniques used by lattice field theorists.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·347 citations
4. 04*

   O(a) improved Wilson quark action on anisotropic lattice

   T. Umeda (CCP, Univ. Tsukuba)🇯🇵 · H. Matsufuru🇯🇵 · T. Onogi (YITP, Kyoto Univ.)🇯🇵

   The $O(a)$ improved Wilson quark action on the anisotropic lattice is investigated. We carry out numerical simulations in the quenched approximation at three values of lattice spacing ($a_{\sigma }^{-1}=1$--2 GeV) with the anisotropy $\xi =a_{\sigma }/a_{\tau }=4$, where $a_{\sigma }$ and $a_{\tau }$ are the spatial and the temporal lattice spacings, respectively. Using the dispersion relation of mesons, the bare anisotropy ${\gamma }_F$ in the quark action is numerically tuned below the charm quark mass region with the statistical accuracy of 1 % level. The systematic uncertainties in the calibration are examined and found to be under control in the continuum limit. Then we compute the light hadron masses and find that they are consistent with the result of the UKQCD Collaboration on the isotropic lattice. The effect of the uncertainty in the calibration on the hadron spectrum for physical quark masses is also found to be under control.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·1 citation
5. 05*

   Anisotropic Lattice and Its Application to Quark Gluon Plasma

   Sunao Sakai (Faculty of Education, Yamagata University)🇯🇵 · Atsushi Nakamura (Information Media Center, Hiroshima University)🇯🇵 · Takuya Saito (Department of Physics, Hiroshima University)🇯🇵

   We have studied the link-integration method for the improved actions. With this method the $\eta$ parameter in the medium to strong coupling regions is obtained. Effects of the self-energy terms for the $\eta$ parameters are small in the regions of $\beta$ and $\eta$ studied. After these investigations, the anisotropic lattice is used for the calculation of transport coefficients of the quark gluon plasma.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·6 citations
6. 06*

   Heavy quark expansion parameters from lattice NRQCD

   JLQCD Collaboration: N. Tsutsui🇯🇵 · S. Aoki🇯🇵 · R. Burkhalter🇯🇵 · M. Fukugita🇯🇵 · S. Hashimoto🇯🇵 · K-I. Ishikawa🇯🇵 · N. Ishizuka🇯🇵 · Y. Iwasaki🇯🇵 · K. Kanaya🇯🇵 · T. Kaneko🇯🇵 · Y. Kuramashi🇯🇵 · M. Okawa🇯🇵 and 5 other authors

   Using the lattice NRQCD action for heavy quark, we calculate the heavy quark expansion parameters ${\mu }_{\pi }^2$ and ${\mu }_G^2$ for heavy-light mesons and heavy-light-light baryons. The results are compared with the mass differences among heavy hadrons to test the validity of HQET relations on the lattice.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·2 citations
7. 07*

   Exploration of sea quark effects in two-flavor QCD with the O(a)-improved Wilson quark action

   JLQCD Collaboration: S. Aoki🇯🇵 · R. Burkhalter🇯🇵 · M. Fukugita🇯🇵 · S. Hashimoto🇯🇵 · K-I. Ishikawa🇯🇵 · N. Ishizuka🇯🇵 · Y. Iwasaki🇯🇵 · K. Kanaya🇯🇵 · T. Kaneko🇯🇵 · Y. Kuramashi🇯🇵 · M. Okawa🇯🇵 · T. Onogi🇯🇵 and 5 other authors

   We explore sea quark effects in the light hadron mass spectrum in a simulation of two-flavor QCD using the nonperturbatively O(a)-improved Wilson fermion action. In order to identify finite-size effects, light meson masses are measured on 12^3x48, 16^3x48 and 20^3x48 lattices with a~0.1 fm. On the largest lattice, where the finite-size effect is negligible, we find a significant increase of the strange vector meson mass compared to the quenched approximation. We also investigate the quark mass dependence of pseudoscalar meson masses and decay constants and test the consistency with (partially quenched) chiral perturbation theory.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·16 citations
8. 08*

   Speeding up the Hybrid-Monte-Carlo algorithm for dynamical fermions

   M. Hasenbusch🇩🇪 · K. Jansen🇩🇪

   We propose a modification of the Hybrid-Monte-Carlo algorithm that allows for a larger step-size of the integration scheme at constant acceptance rate. The key ingredient is the splitting of the pseudo-fermion action into two parts. We test our proposal at the example of the two-dimensional lattice Schwinger model and four-dimensional lattice QCD with two degenerate flavours of Wilson- fermions.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·16 citations
9. 09*

   The Pion Light-Cone Wave Function Phi_pi on the lattice: a partonic signal?

   A. Abada🇫🇷 · Ph. Boucaud🇫🇷 · G. Herdoiza🇫🇷 · J.P. Leroy🇫🇷 · J. Micheli🇫🇷 · O. Pene🇫🇷 · J. Rodriguez-Quintero🇪🇸

   We determine the conditions required to study the pion light-cone wave function Phi_pi with a new method: a direct display of the partons constituting the pion. We present the preliminary results of a lattice computation of Phi_pi following this direction. An auxiliary scalar-quark is introduced. The spectroscopy of its bound states is studied. We observe some indications of a partonic behavior of the system of this scalar-quark and the anti-quark.

   hep-latNucl.Phys.B Proc.Suppl.(2002)·3 citations
10. 10*

    Lattice QCD at finite temperature: Evidence for calorons from the eigenvectors of the Dirac operator

    C. Gattringer🇩🇪 · M. Göckeler🇩🇪 · P.E.L. Rakow🇩🇪 · A. Schäfer🇩🇪 · W. Söldner🇩🇪 · T. Wettig🇺🇸

    We analyze the eigenvalues and eigenvectors of the staggered Dirac operator in quenched lattice QCD in the vicinity of the deconfinement phase transition using the Lüscher-Weisz gauge action. The spectral and localization properties of the low-lying eigenmodes show characteristic differences between the Z_3 sectors above the critical temperature T_c. These findings can be interpreted in terms of calorons.

    hep-latNucl.Phys.B Proc.Suppl.(2002)·8 citations
11. 11*

    Effects of Quenching and Partial Quenching on QCD Penguin Matrix Elements

    Maarten Golterman🇺🇸 · Elisabetta Pallante🇮🇹

    We point out that chiral transformation properties of penguin operators change in the transition from unquenched to (partially) quenched QCD. The way in which this affects the lattice determination of weak matrix elements can be understood in the framework of (partially) quenched chiral perturbation theory.

    hep-latNucl.Phys.B Proc.Suppl.(2002)·16 citations
12. 12*

    Quenched Results for Light Quark Physics with Overlap Fermions

    L. Giusti🇫🇷 · C. Hoelbling🇩🇪 · C. Rebbi🇺🇸

    We present results of a quenched QCD simulation with overlap fermions on a lattice of volume V = 16^3X32 at beta=6.0, which corresponds approximatively to a lattice cutoff of 2 GeV and an extension of 1.4 fm. From the two-point correlation functions of bilinear operators we extract the pseudoscalar meson masses and the corresponding decay constants. From the GMOR relation we determine the chiral condensate and, by using the K-meson mass as experimental input, we compute the sum of the strange and average up-down quark masses (m_s + \hat m). The needed logarithmic divergent renormalization constant Z_S is computed with the RI/MOM non-perturbative renormalization technique. Since the overlap preserves chiral symmetry at finite cutoff and volume, no divergent quark mass and chiral condensate additive renormalizations are required and the results are O(a) improved.

    hep-latNucl.Phys.B Proc.Suppl.(2002)·33 citations
13. 13*

    Im$A_0$, Im$A_2$, and ${ϵ}^{\prime }$ from quenched lattice QCD

    T. Blum · RBC Collaboration

    We present results for the imaginary parts of the I=0 and 2 $K\to \pi \pi$ decay amplitudes, Im$A_{0,2}$, and the ratio of CP violation parameters, ${ϵ}^{\prime }/ϵ$. Our calculation is done in the quenched approximation at $a^{-1}\approx 2$ GeV, lattice size $16^3\times 32$, using domain wall fermions with $L_s=16$. We study the three flavor case (charm is not an active flavor) and find ${ϵ}^{\prime }/ϵ$ is small and slightly negative.

    hep-lathep-phNucl.Phys.B Proc.Suppl.(2002)·6 citations
14. 14*

    The Low-lying Dirac Eigenmodes from Domain Wall Fermions

    Guofeng Liu🇺🇸

    We calculate the low-lying eigenvalues and eigenvectors of the hermitian domain wall Dirac operator on various gauge backgrounds by Ritz minimization. The mass dependence of these eigenvalues is studied to extract the physical 4 dimensional $\lambda$, whose spectral density is related to $<\bar{\psi }\psi >$ through the Banks-Casher relation, and $\delta m$, which represents the effects of the residual chiral symmetry breaking in domain wall formalism on a per eigenmode basis. The topological structure of the underlying gauge field is examined by measuring the ${\Gamma }_5$ matrix elements between the low-lying eigenmodes.

    hep-latNucl.Phys.B Proc.Suppl.(2002)·0 citations
15. 15*

    Chiral Loop Effects in the Quenched Scalar Isovector Propagator

    W. Bardeen · A. Duncan · E. Eichten · H. Thacker

    The scalar isovector meson propagator is studied in quenched QCD. For the lightest quark masses used, this propagator is dominated by a quenched chiral loop effect associated with the ${\eta }^{\prime }$-$\pi$ two-meson intermediate state. Both the time dependence and the pion mass dependence of the effect are well-described by quenched chiral perturbation theory.

    hep-latNucl.Phys.B Proc.Suppl.(2002)·2 citations
16. 16*

    SU(2) Running Coupling Constant and Confinement in Minimal Coulomb and Landau Gauges

    Attilio Cucchieri🇧🇷 · Tereza Mendes🇧🇷 · Daniel Zwanziger🇺🇸

    We present a numerical study of the space-space and time-time components of the gluon propagator at equal time in the minimal Coulomb gauge, and of the gluon and ghost propagators in the minimal Landau gauge. This work allows a non-perturbative evaluation of the running coupling constant and a numerical check of Gribov's confinement scenarios for these two gauges. Our simulations are done in pure SU(2) lattice gauge theory at $\beta =2.2$. We consider several lattice volumes in order to control finite-volume effects and extrapolate our results to infinite lattice volume.

    hep-latNucl.Phys.B Proc.Suppl.(2002)·22 citations
17. 17*

    Confinement made simple in the Coulomb gauge

    Attilio Cucchieri🇧🇷 · Daniel Zwanziger🇺🇸

    In Gribov's scenario in Coulomb gauge, confinement of color charge is due to a long-range instantaneous color-Coulomb potential V(R). This may be determined numerically from the instantaneous part of the gluon propagator D_{44, inst} = V(R) \delta(t). Confinement of gluons is reflected in the vanishing at k = 0 of the equal-time three-dimensionally transverse would-be physical gluon propagator D^{tr}(k). We present exact analytic results on D_{44} and D^{tr} (which have also been investigated numerically, A. Cucchieri, T. Mendes, and D. Zwanziger, this conference), in particular the vanishing of D^{tr}(k) at k = 0, and the determination of the running coupling constant from x_0 g^2(k) = k^2 D_{44, inst}, where x_0 = 12N/(11N-2N_f).

    hep-latNucl.Phys.B Proc.Suppl.(2002)·11 citations
18. 18*

    Dynamic Critical Behavior of an Extended Reptation Dynamics for Self-Avoiding Walks

    Sergio Caracciolo🇮🇹 · Mauro Papinutto🇮🇹 · Andrea Pelissetto🇮🇹

    We consider lattice self-avoiding walks and discuss the dynamic critical behavior of two dynamics that use local and bilocal moves and generalize the usual reptation dynamics. We determine the integrated and exponential autocorrelation times for several observables, perform a dynamic finite-size scaling study of the autocorrelation functions, and compute the associated dynamic critical exponents $z$. For the variables that describe the size of the walks, in the absence of interactions we find $z\approx 2.2$ in two dimensions and $z\approx 2.1$ in three dimensions. At the $\theta$-point in two dimensions we have $z\approx 2.3$.

    ↳ cond-mat.stat-mechhep-latPRE(2002)·1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.