Nucleon and Pion Form Factors from Nf=2+1 Anisotropic Lattices

الأصل · EN

We report a recent lattice-QCD calculation of nucleon and pion electromagnetic form factors and nucleon axial form factors, with special emphasis on large Q². Conventional lattice form-factor calculations can only reach about 2.5 GeV², but in this work the transfer momentum is pushed as large as 6 GeV². Here, we demonstrate the results on 2+1-flavor anisotropic clover lattices for the nucleon and pion, comparing with low-Q² quantities, such as Dirac and Pauli radii, anomalous magnetic moments, gₐ and Mₐ. Our approach can be applied to isotropic lattices and lattices with smaller lattice spacing to achieve even larger-Q² form factors. The form factors are processed to obtain transverse charge and magnetization densities across 2-dimensional impact-parameter space. These measurements could give important theoretical input to experiments, such as those of JLab's 12-GeV program, and provide insight into hadronic structure.