Nucleon electromagnetic and gravitational form factors from holography

Abstract

The electromagnetic form factors of nucleons are calculated using an anti--de Sitter (AdS)/QCD model by considering a Dirac field coupled to a vector field in the five-dimensional AdS space. We also calculate a gravitational or energy-momentum form factor by perturbing the metric from the static AdS solution. We consider both the hard-wall model where the AdS geometry is cut off at ${z}_{0}$ and the soft-wall model where the geometry is smoothly cut off by a background dilaton field.