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Title: Role of the U(1) ghost beyond leading order in a large-Nc expansion

Abstract

The 1/Nc expansion is one of the very few methods we have for generating a systematic expansion of QCD at the energy scale relevant to hadron structure. The present formulation of this theory relies on 't Hooft's double-line notation for calculating the leading order of a diagram in the 1/Nc expansion, where the local SU(Nc) gauge symmetry is substituted by a U(Nc) symmetry and the associated U(1) ghost field is ignored. In the current work we demonstrate the insufficiency of this formulation for describing certain non-planar diagrams. We derive a more complete set of Feynman rules that include the U(1) ghost field and provide a useful tool for calculating both color factors and 1/Nc orders of given color-singlet diagrams.

Authors:
;
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA
Sponsoring Org.:
USDOE - Office of Energy Research (ER)
OSTI Identifier:
910917
Report Number(s):
JLAB-THY-07-701; DOE/OR/23177-0108
TRN: US0800570
DOE Contract Number:  
AC05-06OR23177
Resource Type:
Journal Article
Journal Name:
Journal of Physics G
Additional Journal Information:
Journal Volume: 35; Journal Issue: 11
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COLOR; HADRONS; QUANTUM CHROMODYNAMICS; SYMMETRY

Citation Formats

Matevosyan, Hrayr, and Thomas, Anthony. Role of the U(1) ghost beyond leading order in a large-Nc expansion. United States: N. p., 2008. Web. doi:10.1088/0954-3899/35/11/115006.
Matevosyan, Hrayr, & Thomas, Anthony. Role of the U(1) ghost beyond leading order in a large-Nc expansion. United States. https://doi.org/10.1088/0954-3899/35/11/115006
Matevosyan, Hrayr, and Thomas, Anthony. Mon . "Role of the U(1) ghost beyond leading order in a large-Nc expansion". United States. https://doi.org/10.1088/0954-3899/35/11/115006. https://www.osti.gov/servlets/purl/910917.
@article{osti_910917,
title = {Role of the U(1) ghost beyond leading order in a large-Nc expansion},
author = {Matevosyan, Hrayr and Thomas, Anthony},
abstractNote = {The 1/Nc expansion is one of the very few methods we have for generating a systematic expansion of QCD at the energy scale relevant to hadron structure. The present formulation of this theory relies on 't Hooft's double-line notation for calculating the leading order of a diagram in the 1/Nc expansion, where the local SU(Nc) gauge symmetry is substituted by a U(Nc) symmetry and the associated U(1) ghost field is ignored. In the current work we demonstrate the insufficiency of this formulation for describing certain non-planar diagrams. We derive a more complete set of Feynman rules that include the U(1) ghost field and provide a useful tool for calculating both color factors and 1/Nc orders of given color-singlet diagrams.},
doi = {10.1088/0954-3899/35/11/115006},
url = {https://www.osti.gov/biblio/910917}, journal = {Journal of Physics G},
number = 11,
volume = 35,
place = {United States},
year = {2008},
month = {9}
}