Light-front representation of chiral dynamics in peripheral transverse densities

Abstract

The nucleon's electromagnetic form factors are expressed in terms of the transverse densities of charge and magnetization at fixed light-front time. At peripheral transverse distances $b=O(M_{\pi }^{-1})$ the densities are governed by chiral dynamics and can be calculated model-independently using chiral effective field theory (EFT). We represent the leading-order chiral EFT results for the peripheral transverse densities as overlap integrals of chiral light-front wave functions, describing the transition of the initial nucleon to soft pion-nucleon intermediate states and back. The new representation (a) explains the parametric order of the peripheral transverse densities; (b) establishes an inequality between the spin-independent and -dependent densities; (c) exposes the role of pion orbital angular momentum in chiral dynamics; (d) reveals a large left-right asymmetry of the current in a transversely polarized nucleon and suggests a simple interpretation. The light-front representation enables a first-quantized, quantum-mechanical view of chiral dynamics that is fully relativistic and exactly equivalent to the second-quantized, field-theoretical formulation. It relates the charge and magnetization densities measured in low-energy elastic scattering to the generalized parton distributions probed in peripheral high-energy scattering processes. The method can be applied to nucleon form factors of other operators, e.g. the energy-momentum tensor.

28 pages, 9 figures

References in corpus (4)

• Dispersion analysis of the nucleon form factors including meson continua
• The size of the proton - closing in on the radius puzzle
• Empirical transverse charge densities in the nucleon and the nucleon-to-$\Delta$ transition
• Breakdown of chiral expansion for parton distributions

Cited by in corpus (13)

• Pion structure function from leading neutron electroproduction and SU(2) flavor asymmetry
• Nucleon form factors in dispersively improved Chiral Effective Field Theory I: Scalar form factor
• Nucleon form factors in dispersively improved Chiral Effective Field Theory II: Electromagnetic form factors
• Electron-deuteron deep-inelastic scattering with spectator nucleon tagging and final-state interactions at intermediate x
• Peripheral transverse densities of the baryon octet from chiral effective field theory and dispersion analysis
• Chiral Light Front Perturbation Theory and the Flavor Dependence of the Light-Quark Nucleon Sea
• Forces inside a strongly-coupled scalar nucleon
• Light-front representation of chiral dynamics with Delta isobar and large-N_c relations
• Partonic angular momentum in the nucleon's chiral periphery
• Quantum-mechanical picture of peripheral chiral dynamics
• Transverse charge and current densities in the nucleon from dispersively improved chiral effective field theory
• Pions in Proton Structure and Everywhere Else
• Transverse densities of octet baryons from chiral effective field theory