Axial nucleon and nucleon to {delta} form factors and the Goldberger-Treiman relations from lattice QCD
- Department of Physics, University of Cyprus, CY-1678 Nicosia (Cyprus)
- Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
- Institute for Accelerating Systems and Applications, University of Athens, Athens (Greece)
We evaluate the nucleon axial form factor, G{sub A}(q{sup 2}), and induced pseudoscalar form factor, G{sub p}(q{sup 2}), as well as the pion-nucleon form factor, G{sub {pi}}{sub NN}(q{sup 2}), in lattice QCD. We also evaluate the corresponding nucleon to {delta} transition form factors, C{sub 5}{sup A}(q{sup 2}) and C{sub 6}{sup A}(q{sup 2}), and the pion-nucleon-{delta} form factor G{sub {pi}}{sub N{delta}}(q{sup 2}). The nucleon form factors are evaluated in the quenched theory and with two degenerate flavors of dynamical Wilson fermions. The nucleon to {delta} form factors, besides Wilson fermions, are evaluated using domain wall valence fermions with staggered sea quark configurations for pion masses as low as about 350 MeV. Using these form factors, together with an evaluation of the renormalized quark mass, we investigate the validity of the diagonal and nondiagonal Goldberger-Treiman relations. The ratios G{sub {pi}}{sub N{delta}}(q{sup 2})/G{sub {pi}}{sub NN}(q{sup 2}) and 2C{sub 5}{sup A}(q{sup 2})/G{sub A}(q{sup 2}) are constant as a function of the momentum transfer squared and show almost no dependence on the quark mass. We confirm equality of these two ratios consistent with the Goldberger-Treiman relations extracting a mean value of 1.61(2)
- OSTI ID:
- 21032592
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 76, Issue 9; Other Information: DOI: 10.1103/PhysRevD.76.094511; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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