Chiral dynamics and peripheral transverse densities
Abstract
In the partonic (or light-front) description of relativistic systems the electromagnetic form factors are expressed in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral components of nucleon structure as the peripheral densities at transverse distances b = O(M{sub {pi}}{sup -1}) and compute them in a parametrically controlled manner. A dispersion relation connects the large-distance behavior of the transverse charge and magnetization densities to the spectral functions of the Dirac and Pauli form factors near the two--pion threshold at timelike t = 4 M{ sub {pi}}{sup 2}, which can be computed in relativistic chiral effective field theory. Using the leading-order approximation we (a) derive the asymptotic behavior (Yukawa tail) of the isovector transverse densities in the "chiral" region b = O(M{sub {pi}}{sup -1}) and the "molecular" region b = O(M{sub N}{sup 2}/M{sub {pi}}{sup 3}); (b) perform the heavy-baryon expansion of the transverse densities; (c) explain the relative magnitude of the peripheral charge and magnetization densities in a simple mechanical picture; (d) include Delta isobar intermediate states and study the peripheral transverse densities in the large-N{ sub c} limit of QCD; (e) quantify the region of transverse distances where the chiral componentsmore »
- Authors:
-
- Uppsala University (Sweden)
- JLAB, Newport News, VA (United States)
- Publication Date:
- Research Org.:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC)
- OSTI Identifier:
- 1117511
- Report Number(s):
- JLAB-THY-13-1763; DOE/OR-23177-2641
Journal ID: ISSN 1029-8479; TRN: US1400167
- DOE Contract Number:
- AC05-06OR23177
- Resource Type:
- Journal Article
- Journal Name:
- Journal of High Energy Physics (Online)
- Additional Journal Information:
- Journal Volume: 1401; Journal ID: ISSN 1029-8479
- Publisher:
- Springer Berlin
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Elastic form factors, dispersion relations, chiral effective field theory, 1/Nc expansion, transverse charge and magnetization densities, generalized parton distributions, light–front quantization
Citation Formats
Granados, Carlos G., and Weiss, Christian. Chiral dynamics and peripheral transverse densities. United States: N. p., 2014.
Web. doi:10.1007/JHEP01(2014)092.
Granados, Carlos G., & Weiss, Christian. Chiral dynamics and peripheral transverse densities. United States. https://doi.org/10.1007/JHEP01(2014)092
Granados, Carlos G., and Weiss, Christian. Wed .
"Chiral dynamics and peripheral transverse densities". United States. https://doi.org/10.1007/JHEP01(2014)092. https://www.osti.gov/servlets/purl/1117511.
@article{osti_1117511,
title = {Chiral dynamics and peripheral transverse densities},
author = {Granados, Carlos G. and Weiss, Christian},
abstractNote = {In the partonic (or light-front) description of relativistic systems the electromagnetic form factors are expressed in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral components of nucleon structure as the peripheral densities at transverse distances b = O(M{sub {pi}}{sup -1}) and compute them in a parametrically controlled manner. A dispersion relation connects the large-distance behavior of the transverse charge and magnetization densities to the spectral functions of the Dirac and Pauli form factors near the two--pion threshold at timelike t = 4 M{ sub {pi}}{sup 2}, which can be computed in relativistic chiral effective field theory. Using the leading-order approximation we (a) derive the asymptotic behavior (Yukawa tail) of the isovector transverse densities in the "chiral" region b = O(M{sub {pi}}{sup -1}) and the "molecular" region b = O(M{sub N}{sup 2}/M{sub {pi}}{sup 3}); (b) perform the heavy-baryon expansion of the transverse densities; (c) explain the relative magnitude of the peripheral charge and magnetization densities in a simple mechanical picture; (d) include Delta isobar intermediate states and study the peripheral transverse densities in the large-N{ sub c} limit of QCD; (e) quantify the region of transverse distances where the chiral components of the densities are numerically dominant; (f) calculate the chiral divergences of the b{sup 2}-weighted moments of the isovector transverse densities (charge and anomalous magnetic radii) in the limit M{sub {pi}} -> 0 and determine their spatial support. Our approach provides a concise formulation of the spatial structure of the nucleon's chiral component and offers new insights into basic properties of the chiral expansion. It relates the information extracted from low-t elastic form factors to the generalized parton distributions probed in peripheral high-energy scattering processes.},
doi = {10.1007/JHEP01(2014)092},
url = {https://www.osti.gov/biblio/1117511},
journal = {Journal of High Energy Physics (Online)},
issn = {1029-8479},
number = ,
volume = 1401,
place = {United States},
year = {2014},
month = {1}
}