34 research outputs found
Non-Perturbative Renormalization of the Lattice Heavy Quark Classical Velocity
We discuss the renormalization of the lattice formulation of the Heavy Quark
Effective Theory (LHQET). In addition to wave function and composite operator
renormalizations, on the lattice the classical velocity is also renormalized.
The origin of this renormalization is the reduction of Lorentz (or O(4))
invariance to (hyper)cubic invariance. We present results of a new, direct
lattice simulation of this finite renormalization, and compare the results to
the perturbative (one loop) result. The simulation results are obtained with
the use of a variationally optimized heavy-light meson operator, using an
ensemble of lattices provided by the Fermilab ACP-MAPS collaboration.Comment: 3 pages, postscript compressed with uufiles, TeX not available; Talk
presented at LATTICE96(heavy quarks
Gauge Fixing and the Gibbs Phenomenon
We address the question of why global gauge fixing, specifically to the
lattice Landau gauge, becomes an extremely lengthy process for large lattices.
We construct an artificial "gauge-fixing" problem which has the essential
features encountered in actuality. In the limit in which the size of the system
to be gauge fixed becomes infinite, the problem becomes equivalent to finding a
series expansion in functions which are related to the Jacobi polynomials. The
series converges slowly, as expected. It also converges non-uniformly, which is
an observed characteristic of gauge fixing. In the limiting example, the
non-uniformity arises through the Gibbs phenomenon.Comment: 3 Pages; Talk at Lattice '98; Postscript version only - not available
in te
A New Technique for Measuring the Strangemess Content of the Proton on the Lattice
A new technique for computing the strangeness content of the proton on the
lattice is described. It is applied to the calculation of the strange quark
contribution to the proton's spin, specifically to the evaluation of the proton
matrix element of the strange quark axial current. Preliminary results are not
in disagreement with the EMC experiment. NOTE: This paper is available only in
postscript form.Comment: 8 pages, figures included in the text, all in postscrip
Structural Properties of the Lattice Heavy Quark Effective Theory
We discuss two related aspects of the lattice version of the heavy quark
effective theory (HQET). They are the effects of heavy quark modes with large
momenta, near the boundary of the Brillouin zone, and the renormalization of
the lattice HQET. We argue that even though large momentum modes are present,
their contributions to heavy-light bound states and perturbative loop integrals
are dynamically suppressed and vanish in the continuum limit. We also discuss a
new feature of the renormalization of the lattice HQET not present in the
continuum theory, namely that the classical velocity is finitely renormalized.Comment: 4 pages; postscript; no figures; Talk at Lattice `94 (Bielefeld