arXiv subjects

H. B. Meyer

Publications and source records attributed to H. B. Meyer.

23 records · Page 2Linked to original sources

arXiv2008

Aspects of Precision Calculations of Nucleon Generalized Form Factors with Domain Wall Fermions on an Asqtad Sea

In order to advance lattice calculations of moments of unpolarized, helicity, and transversity distributions, electromagnetic form factors, and generalized form factors of the nucleon to a new level of precision, this work investigates several key aspects of precision lattice calculations. We calculate the number of configurations required for constant statistical errors as a function of pion mass, describe the coherent sink method to help achieve these statistics, examine the statistical correlations between separate measurements, study correlations in the behavior of form factors at different momentum transfer, examine volume dependence, and compare mixed action results with those using comparable dynamical domain wall configurations. We also show selected form factor results and comment on the QCD evolution of our calculations of the flavor non-singlet nucleon angular momentum.

hep-lat↗

arXiv2007

The B-meson mass splitting from non-perturbative quenched lattice QCD

We perform the non-perturbative (quenched) renormalization of the chromo-magnetic operator in Heavy Quark Effective Theory and its three-loop matching to QCD. At order 1/m of the expansion, the operator is responsible for the mass splitting between the pseudoscalar and vector B-mesons. These new computed factors are affected by an uncertainty negligible in comparison to the known bare matrix element of the operator between B-states. Furthermore, they push the quenched determination of the spin splitting for the Bs-meson much closer to its experimental value than the previous perturbatively renormalized computations. The renormalization factor for three commonly used heavy quark actions and the Wilson gauge action and useful parametrizations of the matching coefficient are provided.

hep-lat↗

arXiv2004

Effective gauge theories on domain walls via bulk confinement?

We study with lattice techniques the localisation of gauge fields on domain wall defects in 2+1 dimensions, following a scenario originally proposed by Dvali and Shifman for 3+1 dimensions, based on confining dynamics in the bulk. We find that a localised gauge zero-mode does exist, if the domain wall is wide enough compared with the confinement scale in the bulk. The range of applicability of the corresponding low-energy effective theory is determined by the mass gap to the higher modes. For a wide domain wall, this mass gap is set by ``Kaluza--Klein modes'' as determined by the width. It is pointed out that in this regime the dynamical energy scales generated by the interactions of the localised zero-modes are in fact higher than the mass gap. Therefore, at least in 2+1 dimensions, the zero-modes alone do not form a low-energy effective gauge theory of a traditional type. Finally, we discuss how the situation is expected to change in going to 3+1 dimensions.

hep-ph↗

arXiv2003

Localisation and mass generation for non-Abelian gauge fields

It has been suggested recently that in the presence of suitably "warped" extra dimensions, the low-energy limit of pure gauge field theory may contain massive elementary vector bosons localised on a "brane", but no elementary Higgs scalars. We provide non-perturbative evidence in favour of this conjecture through numerical lattice measurements of the static quark-antiquark force of pure SU(2) gauge theory in three dimensions, of which one is warped. We consider also warpings leading to massless localised vector bosons, and again find evidence supporting the perturbative prediction, even though the gauge coupling diverges far from the brane in this case.

hep-ph↗

arXiv2001

Six-dimensional Abelian vortices with quadratic curvature self-interactions

Six-dimensional Nielsen-Olesen vortices are analyzed in the context of a quadratic gravity theory containing Euler-Gauss-Bonnet self-interactions. The relations among the string tensions can be tuned in such a way that the obtained solutions lead to warped compactification on the vortex. New regular solutions are possible in comparison with the case where the gravity action only consists of the Einstein-Hilbert term. The parameter space of the model is discussed

hep-th↗