Axial nucleon and nucleon to {delta} form factors and the Goldberger-Treiman relations from lattice QCD

Journal Article · Thu Nov 01 04:00:00 EDT 2007 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.76.094511· OSTI ID:21032592

Alexandrou, C; Koutsou, G; Leontiou, Th ^[1]; Negele, J W ^[2]; Tsapalis, A ^[3]

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1. Department of Physics, University of Cyprus, CY-1678 Nicosia (Cyprus)
2. Center for Theoretical Physics, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
3. 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, Journal Name: Physical Review. D, Particles Fields Journal Issue: 9 Vol. 76; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
EVALUATION
FLAVOR MODEL
FORM FACTORS
GOLDBERGER-TREIMAN RELATION
LATTICE FIELD THEORY
MEV RANGE
MOMENTUM TRANSFER
NUCLEONS
PIONS
QUANTUM CHROMODYNAMICS
QUARKS
REST MASS
VALENCE
WILSON LOOP