Nucleon axial and pseudoscalar form factors from the covariant Faddeev equation

Abstract

We compute the axial and pseudoscalar form factors of the nucleon in the Dyson-Schwinger approach. To this end, we solve a covariant three-body Faddeev equation for the nucleon wave function and determine the matrix elements of the axialvector and pseudoscalar isotriplet currents. Our only input is a well-established and phenomenologically successful ansatz for the nonperturbative quark-gluon interaction. As a consequence of the axial Ward-Takahashi identity that is respected at the quark level, the Goldberger-Treiman relation is reproduced for all current-quark masses. We discuss the timelike pole structure of the quark-antiquark vertices that enters the nucleon matrix elements and determines the momentum dependence of the form factors. Our result for the axial charge underestimates the experimental value by 20-25% which might be a signal of missing pion-cloud contributions. The axial and pseudoscalar form factors agree with phenomenological and lattice data in the momentum range above Q^2 ~ 1...2 GeV^2.

17 pages, 7 figures, 1 table

References in corpus (23)

• Infrared Properties of QCD from Dyson-Schwinger equations
• First Measurement of the Muon Neutrino Charged Current Quasielastic Double Differential Cross Section
• Sketching the Bethe-Salpeter kernel
• The nucleon axial mass and the MiniBooNE Quasielastic Neutrino-Nucleus Scattering problem
• Interaction model for the gap equation
• A study of quasi-elastic muon neutrino and antineutrino scattering in the NOMAD experiment
• Dressed-quark anomalous magnetic moments
• The quark-gluon vertex in Landau gauge QCD: Its role in dynamical chiral symmetry breaking and quark confinement
• Nucleon electromagnetic form factors from the covariant Faddeev equation
• Model independent determination of the axial mass parameter in quasielastic neutrino-nucleon scattering
• Perspective on rainbow-ladder truncation
• Axial coupling constant of the nucleon for two flavours of dynamical quarks in finite and infinite volume
• Beyond the rainbow: effects from pion back-coupling
• Measurement of the Rate of Muon Capture in Hydrogen Gas and Determination of the Proton's Pseudoscalar Coupling $g_P$
• Bottomonium in a Bethe-Salpeter-equation study
• Delta and Omega masses in a three-quark covariant Faddeev approach
• Delta and Omega electromagnetic form factors in a Dyson-Schwinger/Bethe-Salpeter approach
• U_A(1) anomaly and eta' mass from an infrared singular quark-gluon vertex
• Hadron Physics and the Dyson--Schwinger Equations of QCD
• Chiral extrapolation of g_A with explicit Delta(1232) degrees of freedom
• Delta-baryon mass in a covariant Faddeev approach
• Nucleon Form Factors of the Isovector Axial-Vector Current: Situation of Experiments and Theory
• Delta properties in the rainbow-ladder truncation of Dyson-Schwinger equations

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