Glueball Matrix Elements on Anisotropic Lattices

The glueball-to-vacuum matrix elements of local gluonic operators in scalar, tensor, and pseudoscalar channels are investigated numerically on several anisotropic lattices with the spatial lattice spacing in the range 0.1fm -- 0.2fm. These matrix elements are needed to predict the glueball branching ratios in $J/\psi$ radiative decays which will help to identify the glueball states in experiments. Two types of improved local gluonic operators are constructed for a self-consistent check, and the finite volume effects are also studied. The lattice spacing dependence of our results is very small and the continuum limits are reliably extrapolated.Comment: 3 pages, 3 figures, Lattice2003 (spectrum

Nucleon, Δ\Delta and Ω\Omega excited states in Nf=2+1N_f=2+1 lattice QCD

The energies of the excited states of the Nucleon, $\Delta$ and $\Omega$ are computed in lattice QCD, using two light quarks and one strange quark on anisotropic lattices. The calculation is performed at three values of the light quark mass, corresponding to pion masses $m_{\pi}$ = 392(4), 438(3) and 521(3) MeV. We employ the variational method with a large basis of interpolating operators enabling six energies in each irreducible representation of the lattice to be distinguished clearly. We compare our calculation with the low-lying experimental spectrum, with which we find reasonable agreement in the pattern of states. The need to include operators that couple to the expected multi-hadron states in the spectrum is clearly identified.Comment: Revised for publication. References added, Table VI expanded to add strange baryon multiparticle thresholds and multiparticle thresholds added to Figs. 4, 5 and 6. 15 pages, 6 figure

The glueball spectrum from an anisotropic lattice study

The spectrum of glueballs below 4 GeV in the SU(3) pure-gauge theory is investigated using Monte Carlo simulations of gluons on several anisotropic lattices with spatial grid separations ranging from 0.1 to 0.4 fm. Systematic errors from discretization and finite volume are studied, and the continuum spin quantum numbers are identified. Care is taken to distinguish single glueball states from two-glueball and torelon-pair states. Our determination of the spectrum significantly improves upon previous Wilson action calculations.Comment: 14 pages, 8 figures, uses REVTeX and epsf.sty (final version published in Physical Review D

Charmonium Spectrum on dynamical anisotropic lattices

We present a first study of the charmonium spectrum on N_f=2 dynamical, anisotropic lattices. We take advantage of all-to-all quark propagators to build spatially extended interpolating operators to increase the overlap with states not easily accessible with point propagators such as radially excited states of eta_c, psi, and chi_c, D-waves and hybrid states.Comment: 9 pages, 7 figures, Lattice 2005 Conferenc

Gallows Variants as Null Characters in the Voynich Manuscript

This study intended to determine how the elimination of gallows variants from the transcription set change the results of statistical queries on the Voynich manuscript. It was hypothesized that the gallows variants in the Voynich manuscript alphabet are null characters, and that removing them would not have a statistically relevant impact on correlational power curves. Voynich-based text samples were created that manipulated and removed gallows variants in different ways. These were analyzed and compared to the original text, looking for similarity and divergence. The actual analysis was a straightforward application of Spearman's rank correlation coefficient to nine separate data samples, along with the source text and two natural language control files written in vulgate Latin and Arabic, respectively. The study demonstrated that the removal of gallows variants effected the statistical measures in ways inconsistent with null characters

The Persistence of Highly Restrictive Special Education Placements for Students with Low- Incidence Disabilities

The purpose of this study is to analyze the Least Restrictive Environment (LRE) data that states and U.S. territories report from the Office of Special Education Programs and discuss the status of the most restrictive special education placement settings for students with disabilities. In this analysis, we found that (1) states do not set rigorous improvement goals to reduce restrictive placements; (2) that the percentage of students with disabilities (SWD) placed in restrictive placements have remained essentially unchanged over the past decade; and (3) that students with low-incidence (severe) disabilities are disproportionally placed in restrictive placements. These results suggest that segregated educational experiences continue for thousands of students with disabilities in spite of evidence that shows that opportunities to learn and develop are enhanced in more inclusive educational settings. Factors that contribute to student placement in restrictive settings are discussed

Constrained Curve Fitting

We survey techniques for constrained curve fitting, based upon Bayesian statistics, that offer significant advantages over conventional techniques used by lattice field theorists.Comment: Lattice2001(plenary); plenary talk given by G.P. Lepage at Lattice 2001 (Berlin); 9 pages, 5 figures (postscript specials

One loop renormalisation of Lattice NRQCD currents for semileptonic B→D(∗)B\to D^{(\ast)} decays to order p⃗M\frac{\vec{p}}{M}

We present the results of a perturbative calculation to match the axial and vector currents for semileptonic $B\to D^{(\ast)}$ decays in lattice NRQCD to the continuum \MSb scheme. The matching is performed to $O(\alpha_s\frac{\vec{p}}{M})$ in Feynman gauge and in the on-shell renormalisation scheme. The spatial and temporal components of the currents renormalise differently; to this order the matching involves a straightforward renormalisation for the $V_0$ and $A_k$ currents, and a rank two and four mixing matrix for the $A_0$ and $V_k$ currents respectively. The resultant one loop corrections are of $O(5$, boding well for the accuracy of forthcoming simulations.Comment: 24 Pages, 18 Figure

Mean-Field Theory for Spin Ladders Using Angular-Momentum Coupled Bases

We study properties of two-leg Heisenberg spin ladders in a mean-field approximation using a variety of angular-momentum coupled bases. The mean-field theory proposed by Gopalan, Rice, and Sigrist, which uses a rung basis, assumes that the mean-field ground state consists of a condensate of spin-singlets along the rungs of the ladder. We generalize this approach to larger angular-momentum coupled bases which incorporate---by their mere definition---a substantial fraction of the important short-range structure of these materials. In these bases the mean-field ground-state remains a condensate of spin singlet---but now with each involving a larger fraction of the spins in the ladder. As expected, the ``purity'' of the ground-state, as judged by the condensate fraction, increases with the size of the elementary block defining the basis. Moreover, the coupling to quasiparticle excitations becomes weaker as the size of the elementary block increases. Thus, the weak-coupling limit of the theory becomes an accurate representation of the underlying mean-field dynamics. We illustrate the method by computing static and dynamic properties of two-leg ladders in the various angular-momentum coupled bases.Comment: 28 pages with 8 figure

SU(2) gluon propagator on a coarse anisotropic lattice

We calculated the SU(2) gluon propagator in Landau gauge on an anisotropic coarse lattice with the improved action. The standard and the improved scheme are used to fix the gauge in this work. Even on the coarse lattice the lattice gluon propagator can be well described by a function of the continuous momentum. The effect of the improved gauge fixing scheme is found not to be apparent. Based on the Marenzoni's model, the mass scale and the anomalous dimension are extracted and can be reasonably extrapolated to the continuum limit with the values $\alpha\sim 0.3$ and $M\sim 600MeV$. We also extract the physical anisotropy $\xi$ from the gluon propagator due to the explicit $\xi$ dependence of the gluon propagator.Comment: LaTeX, 14 pages including 4 ps figure