108 research outputs found
Overrelaxed operators in lattice gauge theories
Abstract For operators in lattice gauge theories linear in the link variables we propose improved estimators, obtained from a microcanonical integration of statistically independent links. We give explicit expressions for the SU(2) and the SU(3) cases and we compare the method with the canonical integration based on the multihit technique
Universal continuum limit of non-perturbative lattice non-singlet moment evolution
We present evidence for the universality of the continuum limit of the scale
dependence of the renormalization constant associated with the operator
corresponding to the average momentum of non-singlet parton densities. The
evidence is provided by a non-perturbative computation in quenched lattice QCD
using the Schr\"odinger Functional scheme. In particular, we show that the
continuum limit is independent of the form of the fermion action used, i.e. the
Wilson action and the non-perturbatively improved clover action.Comment: Latex2e file, 2 figures, 9 page
Renormalization group invariant average momentum of non-singlet parton densities
We compute, within the Schr\"odinger functional scheme, a renormalization
group invariant renormalization constant for the first moment of the
non-singlet parton distribution function. The matching of the results of our
non-perturbative calculation with the ones from hadronic matrix elements allows
us to obtain eventually a renormalization group invariant average momentum of
non-singlet parton densities, which can be translated into a preferred scheme
at a specific scale.Comment: Latex2e file, 4 figures, 12 page
Smeared propagators for lattice hadron spectroscopy
We propose to replace ordinary propagators in lattice operator correlations entering the determination of hadron masses with space-time smeared propagators. These are defined as the inverse of the quadratic operator in the fermion action times its hermitian conjugate. We obtain a cleaner determination of hadron masses, comparable to the effect of using smeared operators
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