Fri·Sep 27, 2002Friday·September 27, 2002

1. 01*

   Path Integral Monte Carlo Approach to the U(1) Lattice Gauge Theory in (2+1) Dimensions

   Mushtaq Loan🇦🇺 · Michael Brunner🇦🇺 · Clare Sloggett🇦🇺 · Chris Hamer🇦🇺

   Path Integral Monte Carlo simulations have been performed for U(1) lattice gauge theory in (2+1) dimensions on anisotropic lattices. We extractthe static quark potential, the string tension and the low-lying "glueball" spectrum.The Euclidean string tension and mass gap decrease exponentially at weakcoupling in excellent agreement with the predictions of Polyakov and Göpfert and Mack, but their magnitudes are five times bigger than predicted. Extrapolations are made to the extreme anisotropic or Hamiltonian limit, and comparisons are made with previous estimates obtained in the Hamiltonian formulation.

   hep-latPRD(2003)·40 citations
2. 02*

   Calculation of Moments of Structure Functions

   M. Göckeler🇩🇪 · R. Horsley🇬🇧 · D. Pleiter🇩🇪 · P.E.L. Rakow🇩🇪 · A. Schäfer🇩🇪 · G. Schierholz🇩🇪

   The progress on the lattice computation of low moments of both the unpolarised and polarised nucleon structure functions is reviewed with particular emphasis on continuum and chiral extrapolations and comparison between quenched and unquenched fermions.

   hep-lathep-phNucl.Phys.B Proc.Suppl.(2003)·30 citations
3. 03*

   Mass gap in compact U(1) Model in (2+1) dimensions

   Mushtaq Loan🇦🇺 · Michael Brunner🇦🇺 · Chris Hamer🇦🇺

   A numerical study of low-lying glueball masses of compact U(1) lattice gauge theory in (2+1) dimensions is performed using Standard Path integral Monte Carlo techniques. The masses are extracted, at fixed (low) temperature, from simulations on anisotropic lattices, with temporal lattice spacing much smaller than the spatial ones. Convincing evidence of the scaling behaviour in the antisymmetric mass gap is observed over the range $1.4<\beta <2.25$. The observed behaviour is very consistent with asymptotic form predicted by Göpfert and Mack. Extrapolations are made to the "Hamiltonian" limit, and the results are compared with previous estimates obtained by many other Hamiltonian studies.

   hep-lat2 citations
4. 04*

   Non-perturbative renormalization of HQET and QCD

   Rainer Sommer (DESY Zeuthen)🇩🇪

   We discuss the necessity of non-perturbative renormalization in QCD and HQET and explain the general strategy for solving this problem. A few selected topics are discussed in some detail, namely the importance of off-shell improvement in the MOM-scheme on the lattice, recent progress in the implementation of finite volume schemes and then particular emphasis is put on the recent idea to carry out a non-perturbative renormalization of the Heavy Quark Effective Theory.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·31 citations
5. 05*

   Heavy-light meson decay constants with N_f=3

   MILC Collaboration: C. Bernard (Washington U.)🇺🇸 · T. Burch (U. Arizona)🇺🇸 · S. Datta (U. Bielefeld)🇩🇪 · C. DeTar (U. Utah)🇺🇸 · Steven Gottlieb (Indiana U.)🇺🇸 · E. Gregory (U. Arizona)🇺🇸 · Urs M. Heller (Florida State U.)🇺🇸 · R. Sugar (UC Santa Barbara)🇺🇸 · D. Toussaint (U. Arizona)🇺🇸

   During the past year the MILC Collaboration has continued its study of heavy-light meson decay constants with three dynamical quarks. Calculations have been extended to a second lattice spacing of about 0.09 fm. At this lattice spacing, there are results in the quenched approximation and for three sets of dynamical quark mass: m_l=m_s; m_l=0.4 m_s and m_l=0.2 m_s, where m_l is the light mass for the u and d quarks and m_s is the strange quark mass. At the coarser lattice spacing, for which results were presented at Lattice 2001, statistics have been increased for two sets of quark masses and three additional sets of quark masses have been studied, giving a total of eight combinations used to interpolate between the quenched and chiral limits. When these calculations are completed, we can study the decay constants taking into account both chiral and continuum extrapolations.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·16 citations
6. 06*

   Low Energy Chiral Lagrangian Parameters for Scalar and Pseudoscalar Mesons

   W. Bardeen (Fermilab)🇺🇸 · E. Eichten (Fermilab)🇺🇸 · H. Thacker (Univ. of Virginia)🇺🇸

   We present results of a high-statistics study of scalar and pseudoscalar meson propagators in quenched QCD at two values of lattice spacing, beta = 5.7 and 5.9, with clover-improved Wilson fermions. The study of the chiral limit is facilitated by the pole-shifting ansatz of the modified quenched approximation. Pseudoscalar masses and decay constants are determined as a function of quark mass and quenched chiral log effects are estimated. A study of the flavor singlet eta prime hairpin diagram yields a precise determination of the eta prime mass insertion. The corresponding value of the quenched chiral log parameter delta is compared with the observed QCL effects. Removal of QCL effects from the scalar propagator allows a determination of the mass of the lowest lying isovector scalar $q\bar{q}$ meson.

   hep-latNucl.Phys.B Proc.Suppl.(2003)·5 citations
7. 07*

   Lattice QCD data versus Chiral Perturbation Theory: the case of $M_{\pi }$

   Stephan Dürr🇩🇪

   I present a selection of recent lattice data by major collaborations for the pseudo-Goldstone boson masses in full ($N_f=2$) QCD, where the valence quarks are chosen exactly degenerate with the sea quarks. At least the more chiral points should be consistent with Chiral Perturbation Theory for the latter to be useful in extrapolating to physical masses. Perspectives to reliably determine NLO Gasser-Leutwyler coefficients are discussed.

   ↳ hep-phhep-latNucl.Phys.B Proc.Suppl.(2003)·5 citations
8. 08*

   Ginsparg-Wilson Relation, Topological Invariants and Finite Noncommutative Geometry

   Hajime Aoki🇯🇵 · Satoshi Iso🇯🇵 · Keiichi Nagao🇯🇵

   We show that the Ginsparg-Wilson (GW) relation can play an important role to define chiral structures in {\it finite} noncommutative geometries. Employing GW relation, we can prove the index theorem and construct topological invariants even if the system has only finite degrees of freedom. As an example, we consider a gauge theory on a fuzzy two-sphere and give an explicit construction of a noncommutative analog of the GW relation, chirality operator and the index theorem. The topological invariant is shown to coincide with the 1st Chern class in the commutative limit.

   ↳ hep-thhep-latmath-phmath.MP+1PRD(2003)·59 citations

* 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.