PaperPanorama

HEP Lattice·hep-lat

Thu·Aug 29, 2002

8 papers—7 primary·1 cross-listed·reconstructed*

All8Primary7Cross-lists1
  1. 01*

    Semileptonic B Decays from an NRQCD/D234 Action

    J. Shigemitsu🇺🇸 · S. Collins🇬🇧 · C.T.H. Davies🇬🇧 · J. Hein🇬🇧 · R.R. Horgan🇬🇧 · G.P. Lepage🇺🇸

    Semileptonic B decays are studied on quenched anisotropic lattices using Symanzik improved glue, NRQCD heavy quark and D234 light quark actions. We employ constrained fits to extract ground state contributions to two- and three-point correlators. Results for the B --> pi, l nubar decay form factors are compared with previous lattice results. We find that our systematic errors (excluding quenching errors) are dominated by chiral extrapolation uncertainties.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·5 citations
  2. 02*

    Strange matrix elements of the nucleon

    Randy Lewis🇨🇦 · W. Wilcox🇺🇸 · R.M. Woloshyn🇨🇦

    Results for the disconnected contributions to matrix elements of the vector current and scalar density have been obtained for the nucleon from the Wilson action at beta=6 using a stochastic estimator technique and 2000 quenched configurations. Various methods for analysis are employed and chiral extrapolations are discussed.

    hep-lathep-phNucl.Phys.B Proc.Suppl.(2003)·4 citations
  4. 04*

    Improved Wilson QCD simulations at light quark masses

    A.C. Irving · UKQCD Collaboration

    We present preliminary results from UKQCD simulations at light quark masses using two flavours of non-pertubatively improved Wilson fermions. We report on the performance of the standard HMC algorithm at these quark masses where m_pi/m_rho < 0.5 in comparison with simulations using improved staggered quarks.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·10 citations
  5. 05*

    Quenched chiral logarithms in lattice QCD with overlap Dirac quarks

    Ting-Wai Chiu🇹🇼 · Tung-Han Hsieh🇹🇼

    We examine quenched chiral logarithms in lattice QCD with overlap Dirac quarks. From our data of m_pi^2, we determine the coefficient of quenched chiral logarithm delta = 0.203(14), 0.176(17), 0.193(17) and 0.200(13) for lattices of sizes 8^3 times 24, 10^3 times 24, 12^3 times 24 and 16^3 times 32 respectively. Also, for the first three lattice sizes, we measure the index susceptibility of the overlap Dirac operator, and use the exact relation between the index susceptibility and the eta' mass in quenched chiral perturbation theory to obtain an independent determination of delta = 0.198(27), 0.173(24), 0.169(22), which are in good agreement with those determined from m_pi^2.

    hep-lathep-phhep-thNucl.Phys.B Proc.Suppl.(2003)·4 citations
  6. 06*

    Hamiltonian study of Supersymmetric Yang-Mills Quantum Mechanics

    J. Kotanski🇵🇱 · J. Wosiek🇵🇱

    New results obtained within the recently developed approach to supersymmetric quantum mechanical systems are presented. The method does not suffer from the sign problem in any dimensions and is capable to provide any quantum observable with controllable systematic error. Discussed results include: the spectrum and Witten index of the D=4 system, and the spectrum of zero volume glueballs in higher 3 < D < 11 dimensions.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·14 citations
  7. 07*

    Experiences with the multi-level algorithm

    Pushan Majumdar🇩🇪

    Small expectation values are difficult to measure in Monte Carlo calculations as they tend to get swamped by noise. Recently an algorithm has been proposed by Luscher and Weisz which allows one to measure expectation values which previously could not be measured reliably in Monte Carlo simulations. We will test our implementation of this algorithm by looking at Polyakov loop correlators and then explore ways of applying it for measuring large Wilson loops.

    hep-latNucl.Phys.B Proc.Suppl.(2003)·9 citations
  8. 08*

    Free energy and theta dependence of SU(N) gauge theories

    L. Del Debbio (1)🇮🇹 · H. Panagopoulos (2)🇨🇾 · E. Vicari (1) ((1) University of Pisa and INFN, Pisa, Italy, (2) University of Cyprus, Lefkosia, Cyprus)🇮🇹

    We study the dependence of the free energy on the CP violating angle theta, in four-dimensional SU(N) gauge theories with N >= 3, and in the large-N limit. Using the Wilson lattice formulation for numerical simulations, we compute the first few terms of the expansion of the ground-state energy F(theta) around theta = 0, F(theta) - F(0) = A_2 theta^2 (1 + b_2 theta^2 + ...). Our results support Witten's conjecture: F(theta) - F(0) = A theta^2 + O(1/N) for theta < pi. We verify that the topological susceptibility has a nonzero large-N limit chi_infinity = 2A with corrections of O(1/N^2), in substantial agreement with the Witten-Veneziano formula which relates chi_infinity to the eta' mass. Furthermore, higher order terms in theta are suppressed; in particular, the O(theta^4) term b_2 (related to the eta' - eta' elastic scattering amplitude) turns out to be quite small: b_2 = -0.023(7) for N=3, and its absolute value decreases with increasing N, consistently with the expectation b_2 = O(1/N^2).

    ↳ hep-thhep-latNucl.Phys.B Proc.Suppl.(2003)·0 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.