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Title: Chiral extrapolation of g{sub A} with explicit {delta}(1232) degrees of freedom

Abstract

An updated and extended analysis of the quark-mass dependence of the nucleon's axial-vector coupling constant g{sub A} is presented in comparison with state-of-the-art lattice QCD results. Special emphasis is placed on the role of the {delta}(1232) isobar. It is pointed out that standard chiral perturbation theory of the pion-nucleon system at order p{sup 4} fails to provide an interpolation between the lattice data and the physical point. In constrast, a version of chiral effective field theory with explicit inclusion of the {delta}(1232) proves to be successful. Detailed error analysis and convergence tests are performed. Integrating out the {delta}(1232) as an explicit degree of freedom introduces uncontrolled errors for pion masses m{sub {pi}} > or approx. 300 MeV.

Authors:
; ; ;  [1]
  1. Physik-Department, Theoretische Physik, Technische Universitaet Muenchen, D-85747 Garching (Germany)
Publication Date:
OSTI Identifier:
20933245
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 75; Journal Issue: 1; Other Information: DOI: 10.1103/PhysRevD.75.014503; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CHIRALITY; CONVERGENCE; COUPLING CONSTANTS; DEGREES OF FREEDOM; DELTA-1232 BARYONS; ERRORS; EXTRAPOLATION; INTERPOLATION; MASS; MEV RANGE 100-1000; NUCLEONS; PERTURBATION THEORY; PION-NUCLEON INTERACTIONS; PIONS; QUANTUM CHROMODYNAMICS; QUARKS

Citation Formats

Procura, M., Musch, B. U., Hemmert, T. R., and Weise, W. Chiral extrapolation of g{sub A} with explicit {delta}(1232) degrees of freedom. United States: N. p., 2007. Web. doi:10.1103/PHYSREVD.75.014503.
Procura, M., Musch, B. U., Hemmert, T. R., & Weise, W. Chiral extrapolation of g{sub A} with explicit {delta}(1232) degrees of freedom. United States. doi:10.1103/PHYSREVD.75.014503.
Procura, M., Musch, B. U., Hemmert, T. R., and Weise, W. Mon . "Chiral extrapolation of g{sub A} with explicit {delta}(1232) degrees of freedom". United States. doi:10.1103/PHYSREVD.75.014503.
@article{osti_20933245,
title = {Chiral extrapolation of g{sub A} with explicit {delta}(1232) degrees of freedom},
author = {Procura, M. and Musch, B. U. and Hemmert, T. R. and Weise, W.},
abstractNote = {An updated and extended analysis of the quark-mass dependence of the nucleon's axial-vector coupling constant g{sub A} is presented in comparison with state-of-the-art lattice QCD results. Special emphasis is placed on the role of the {delta}(1232) isobar. It is pointed out that standard chiral perturbation theory of the pion-nucleon system at order p{sup 4} fails to provide an interpolation between the lattice data and the physical point. In constrast, a version of chiral effective field theory with explicit inclusion of the {delta}(1232) proves to be successful. Detailed error analysis and convergence tests are performed. Integrating out the {delta}(1232) as an explicit degree of freedom introduces uncontrolled errors for pion masses m{sub {pi}} > or approx. 300 MeV.},
doi = {10.1103/PHYSREVD.75.014503},
journal = {Physical Review. D, Particles Fields},
number = 1,
volume = 75,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • We present two new nucleon-nucleon (NN) potentials: a v/sub 14/ model that is a conventional NN potential and a v/sub 28/ model with explicit ..delta..(1232) degrees of freedom. The v/sub 14/ model has 14 operator components describing NN channels, while the v/sub 28/ model has 14 additional operators, including 12 transition operators for all possible ..pi..N..delta.. and ..pi delta delta.. couplings and two central operators for N..delta.. and ..delta delta.. channels; the latter are constrained so that the v/sub 28/ model has no additional free parameters for data fitting. The two models give excellent and almost identical fits to deuteronmore » properties and np scattering below 330 MeV. The v/sub 14/ and v/sub 28/ forms are convenient for nuclear structure calculations; when many-body cluster contributions are evaluated the v/sub 28/ model will automatically include much of the effect attributed to many-body forces in conventional models, while the v/sub 14/ model will provide a standard of comparison.« less
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