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Title: Chiral extrapolation of nucleon magnetic form factors

Abstract

The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and all octet and decuplet baryons are included in the intermediate states. Finite range regularization is applied to improve the convergence in the quark-mass expansion. At each value of the momentum transfer (Q{sup 2}), a separate extrapolation to the physical pion mass is carried out as a function of m{sub {pi}} alone. Because of the large values of Q{sup 2} involved, the role of the pion form factor in the standard pion-loop integrals is also investigated. The resulting values of the form factors at the physical pion mass are compared with experimental data as a function of Q{sup 2} and demonstrate the utility and accuracy of the chiral extrapolation methods presented herein.

Authors:
; ; ;
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility, Newport News, VA
Sponsoring Org.:
USDOE - Office of Energy Research (ER)
OSTI Identifier:
897646
Report Number(s):
JLAB-THY-06-593; DOE/OR/23177-0003; hep-ph/0701082
TRN: US0701487
DOE Contract Number:
AC05-06OR23177
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys.Rev.D; Journal Volume: 75; Journal Issue: 7
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ACCURACY; BARYONS; CONVERGENCE; EXTRAPOLATION; FORM FACTORS; MOMENTUM TRANSFER; NUCLEONS; PIONS; QUANTUM CHROMODYNAMICS

Citation Formats

P. Wang, D. Leinweber, A. W. Thomas, and R.Young. Chiral extrapolation of nucleon magnetic form factors. United States: N. p., 2007. Web. doi:10.1103/PhysRevD.75.073012.
P. Wang, D. Leinweber, A. W. Thomas, & R.Young. Chiral extrapolation of nucleon magnetic form factors. United States. doi:10.1103/PhysRevD.75.073012.
P. Wang, D. Leinweber, A. W. Thomas, and R.Young. Sun . "Chiral extrapolation of nucleon magnetic form factors". United States. doi:10.1103/PhysRevD.75.073012. https://www.osti.gov/servlets/purl/897646.
@article{osti_897646,
title = {Chiral extrapolation of nucleon magnetic form factors},
author = {P. Wang and D. Leinweber and A. W. Thomas and R.Young},
abstractNote = {The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and all octet and decuplet baryons are included in the intermediate states. Finite range regularization is applied to improve the convergence in the quark-mass expansion. At each value of the momentum transfer (Q{sup 2}), a separate extrapolation to the physical pion mass is carried out as a function of m{sub {pi}} alone. Because of the large values of Q{sup 2} involved, the role of the pion form factor in the standard pion-loop integrals is also investigated. The resulting values of the form factors at the physical pion mass are compared with experimental data as a function of Q{sup 2} and demonstrate the utility and accuracy of the chiral extrapolation methods presented herein.},
doi = {10.1103/PhysRevD.75.073012},
journal = {Phys.Rev.D},
number = 7,
volume = 75,
place = {United States},
year = {Sun Apr 01 00:00:00 EDT 2007},
month = {Sun Apr 01 00:00:00 EDT 2007}
}
  • The extrapolation of nucleon magnetic form factors calculated within lattice QCD is investigated within a framework based upon heavy baryon chiral effective-field theory. All one-loop graphs are considered at arbitrary momentum transfer and all octet and decuplet baryons are included in the intermediate states. Finite range regularization is applied to improve the convergence in the quark-mass expansion. At each value of the momentum transfer (Q{sup 2}), a separate extrapolation to the physical pion mass is carried out as a function of m{sub {pi}} alone. Because of the large values of Q{sup 2} involved, the role of the pion form factormore » in the standard pion-loop integrals is also investigated. The resulting values of the form factors at the physical pion mass are compared with experimental data as a function of Q{sup 2} and demonstrate the utility and accuracy of the chiral extrapolation methods presented herein.« less
  • We explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon form factors to the physical regime. We find that the lattice results can be reproduced using the Light Front Cloudy Bag Model by letting its parameters be analytic functions of the quark mass. We then use the model to extend the lattice calculations to large values of Q2 of interest to current and planned experiments. These functions are also used to define extrapolations to the physical value of the pion mass, thereby allowing us to study how the predicted zero in GE(Q2)/GM(Q2) varies as amore » function of quark mass.« less
  • We explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon form factors to the physical regime. We find that the lattice results can be reproduced using the light front cloudy bag model by letting its parameters be analytic functions of the quark mass. We then use the model to extend the lattice calculations to large values of Q{sup 2} of interest to current and planned experiments. These functions are also used to define extrapolations to the physical value of the pion mass, thereby allowing us to study how the predicted zero in G{sub E}(Q{sup 2})/G{submore » M}(Q{sup 2}) varies as a function of quark mass.« less