Flavor twisted boundary conditions and isovector form factors

摘要

We use vector flavor symmetry to relate form factors of isospin changing operators to isovector form factors. Flavor twisted boundary conditions in lattice QCD thus allow isovector form factors of twist-two operators, e.g., to be computed at continuous values of the momentum transfer. These twisted boundary conditions, moreover, are implemented only in the valence sector. Effects of the finite volume must be addressed to extract isovector moments and radii from states projected onto zero Fourier momentum. As an example, we use chiral perturbation theory to assess the volume effects in extracting the isovector magnetic moment of the nucleon from simulations with twisted boundary conditions. (c) 2006 Elsevier B.V. All rights reserved.