Lattice HQET Calculation of the Isgur-Wise Function

We calculate the Isgur-Wise function on the lattice, simulating the light quark with the Wilson action and the heavy quark with a direct lattice implementation of the heavy-quark effective theory. Improved smearing functions produced by a variational technique, MOST, are used to reduce the statistical errors and to minimize excited-state contamination of the ground-state signal. Calculating the required matching factors, we obtain $\xi'(1)=-0.64(13)$ for the slope of the Isgur-Wise function in continuum-HQET in the \barMS scheme at a scale of $4.0$GeV.Comment: 3 Pages, LaTeX, Poster at Lattice '9

BB Meson Matrix Elements from Various Heavy Quark Effective Theories

Various properties of heavy-light mesons are determined, including decay constants, the $B_{B}$-parameter, and the Isgur-Wise function. The heavy (bottom) quark is simulated with the static, NRQCD and/or (fixed-velocity) lattice-HQET effective theories, using optimally-smeared sources as produced by the ``Maximal Operator Smearing Technique''.Comment: To appear in the proceedings of the Lattice '95 conference. 4 pages, uuencoded-compressed PostScript fil

NRQCD and Static Systems -- A General Variational Approach

We present initial results from Monte Carlo simulations of NRQCD-light, static-light, and NRQCD-NRQCD mesons, using a variational technique (MOST), as part of our ongoing calculation of the $f_{B}$ decay constant. The basis states for the variational calculation are quark-antiquark operators separated by all possible relative distances not equivalent under the cubic group (for example, for a $20^{3}$ lattice there are 286 operators). The efficacy of the method is demonstrated by the good plateaus obtained for the ground state and the clean extraction of the wave functions of the ground and first radially excited state.Comment: Contribution to the Lattice '94 conference, 3 pages, uuencoded-compressed PostScript fil

A Study of the Static-Light BBB_B Parameter

We calculate the $B_B$ parameter, relevant for $\overline{B}^0$--$B^0$ mixing, from a lattice gauge theory simulation using the static approximation for the heavy quark and the Wilson action for the light quark and gauge fields. Improved sources, produced by an optimized variational technique, {\sc most}, reduce statistical errors and minimize excited-state contamination of the ground-state signal. Renormalization of four-fermion operator coefficients, using the Lepage-Mackenzie procedure for estimating typical momentum scales, is linearized to reduce order $\alpha_s^2$ uncertainties.Comment: 4 pages (LaTeX), Talk presented at LATTICE96(heavy quarks), Minor numerically-insignificant changes made and reference adde

An investigation into a wavelet accelerated gauge fixing algorithm

We introduce an acceleration algorithm for coulomb gauge fixing, using the compactly supported wavelets introduced by Daubechies. The algorithm is similar to Fourier acceleration. Our provisional numerical results for $SU(3)$ on $8^{4}$ lattices show that the acceleration based on the DAUB6 transform can reduce the number of iterations by a factor up to 3 over the unaccelerated algorithm. The reduction in iterations for Fourier acceleration is approximately a factor of 7.Comment: Resubmitted as a uuencode-compressed-tar postscript file. A Daubechies wavelet transform will transform a vector of length $N$ in $O(N)$ operations, and not in O(N log N) operations as we incorrectly stated in the first version of this pape

Variational calculation of heavy-light meson properties

We present a new method for the study of heavy-light mesons in the static approximation of lattice QCD which is optimally effective in isolating ground and excited states. With ``MOST'' (Maximal Operator Smearing Technique), the heavy quark is smeared at all possible positions relative to the light quark, subject to the constraint of cubic symmetry. With correlation functions constructed using this set as a variational basis, eigenstates of the transfer matrix are projected out at very small time separations, where statistical errors are small. We illustrate the utility of the method with preliminary results for the meson decay constant $f_{B}^{\rm stat}$, binding energies and wave functions of the lowest states. The method produces dynamically-improved interpolating fields which can be used for matrix element calculations.Comment: 3pages, uuencode-compressed-tar Postscript file. (160 kbytes), preprint number uk/93-0