Up, down, and strange nucleon axial form factors from lattice QCD
Name
PhysRevD.95.114502.pdf
Size
1.39 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Green, Jeremy
Hasan, Nesreen
Meinel, Stefan
Engelhardt, Michael
Krieg, Stefan
Laeuchli, Jesse
Orginos, Kostas
Syritsyn, Sergey
Pochinsky, Andrew
Negele, John W.
Date Issued
June 2017
Journal
Physical Review D
Publisher
American Physical Society
Citation
Green, Jeremy et al. “Up, Down, and Strange Nucleon Axial Form Factors from Lattice QCD.” Physical Review D 95.11 (2017): n. pag. © 2017 American Physical Society
Version
Final published version
Abstract
We report a calculation of the nucleon axial form factors G[superscript q][superscript A](Q[superscript 2]) and G[superscript q][subscript P](Q[superscript 2]) for all three light quark flavors q ∈ {u,d,s} in the range 0 ≤ Q[superscript 2] ≲ 1.2 GeV[superscript 2] using lattice QCD. This work was done using a single ensemble with pion mass 317 MeV and made use of the hierarchical probing technique to efficiently evaluate the required disconnected loops. We perform nonperturbative renormalization of the axial current, including a nonperturbative treatment of the mixing between light and strange currents due to the singlet-nonsinglet difference caused by the axial anomaly. The form factor shapes are fit using the model-independent z expansion. From G[superscript q][subscript A](Q[superscript 2]), we determine the quark contributions to the nucleon spin and axial radii. By extrapolating the isovector G[superscript u-d][subscript P](Q[superscript 2]), we obtain the induced pseudoscalar coupling relevant for ordinary muon capture and the pion-nucleon coupling constant. We find that the disconnected contributions to G[subscript P] form factors are large, and give an interpretation based on the dominant influence of the pseudoscalar poles in these form factors.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
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DOI of Published Version
https://doi.org/10.1103/PhysRevD.95.114502
