DSE inspired model for the pion's valence dressed-quark GPD

[摘要] We sketch here an approach to the computation of genaralised parton distributions (GPDs), based upon a rainbow-ladder (RL) truncation of QCD's Dyson-Schwinger equations and exemplified via the pion's valence dressed-quark GPD, Hvπ(x,ξ,t). Our analysis focuses on the case of zero skewness, ξ = 0, and underlines that the impulse-approximation used hitherto to define the pion's valence dressed-quark GPD is generally invalid owing to omission of contributions from the gluons which bind dressed-quarks into the pion. A simple correction enables us to identify a practicable improvement to the approximation for Hvπ(x,0,t), expressed as the Radon transform of a single amplitude. Therewith we obtain results for Hvπ(x,0,t) and the associated impact-parameter dependent distribution, , which provide a qualitatively sound picture of the pion's dressed-quark structure at an hadronic scale.

[发布机构] CSSM, School of Chemistry and Physics, University of Adelaide, Adelaide; SA; 5005, Australia^1;Centre de Saclay, IRFU/Service de Physique Nucleaire, Gif-sur-Yvette; F-91191, France^2;Physics Division, Argonne National Laboratory, Argonne; IL; 60439, United States^3;Departamento de Física Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, Huelva; E-21071, Spain^4

[关键词] Impact-parameter;Impulse approximation;Parton distributions;Quark structure;Radon Transform