Light-front representation of chiral dynamics in peripheral transverse densities
2015 (English)In: Journal of High Energy Physics (JHEP), ISSN 1029-8479, E-ISSN 1126-6708, no 7, 170Article in journal (Refereed) Published
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 anti 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.
Place, publisher, year, edition, pages
2015. no 7, 170
Electromagnetic Processes and Properties, Chiral Lagrangians, Parton Model
IdentifiersURN: urn:nbn:se:uu:diva-261260DOI: 10.1007/JHEP07(2015)170ISI: 000358927700002OAI: oai:DiVA.org:uu-261260DiVA: diva2:850082