External Momentum, Volume Effects, and the Nucleon Magnetic Moment

Abstract

We analyze the determination of volume effects for correlation functions that depend on an external momentum. As a specific example, we consider finite volume nucleon current correlators, and focus on the nucleon magnetic moment. Because the multipole decomposition relies on SO(3) rotational invariance, the structure of such finite volume corrections is unrelated to infinite volume multipole form factors. One can deduce volume corrections to the magnetic moment only when a zero-mode photon coupling vanishes, as occurs at next-to-leading order in heavy baryon chiral perturbation theory. To deduce such finite volume corrections, however, one must assume continuous momentum transfer. In practice, volume corrections with momentum transfer dependence are required to address the extraction of the magnetic moment, or other observables that arise in momentum dependent correlation functions. Additionally we shed some light on a puzzle concerning differences in lattice form factor data at equal values of momentum transfer squared.

21 pages, 5 figures; discussion in Sect. IV C expanded, Figs. now B&W friendly

References in corpus (9)

• n-Boson Energies at Finite Volume and Three-Boson Interactions
• Electromagnetic and spin polarisabilities in lattice QCD
• The Delta-resonance in a finite volume
• Fitting two nucleons inside a box: exponentially suppressed corrections to the Luscher's formula
• Flavor Twisted Boundary Conditions and Isovector Form Factors
• Pion Polarizabilities and Volume Effects in Lattice QCD
• Generalised parton distributions of the pion in partially-quenched chiral perturbation theory
• Current Renormalization in Finite Volume
• Calculation of the axial charge in the epsilon and epsilon' regimes of HBChPT

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