Nucleon form factors with 2+1 flavor dynamical domain-wall fermions

Takeshi Yamazaki, Yasumichi Aoki, Tom Blum, Huey Wen Lin, Shigemi Ohta, Shoichi Sasaki, Robert Tweedie, James Zanotti

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131 Citations (Scopus)

Abstract

We report our numerical lattice QCD calculations of the isovector nucleon form factors for the vector and axial-vector currents: the vector, induced tensor, axial-vector, and induced pseudoscalar form factors. The calculation is carried out with the gauge configurations generated with Nf=2+1 dynamical domain-wall fermions and Iwasaki gauge actions at β=2.13, corresponding to a cutoff a-1=1.73GeV, and a spatial volume of (2.7fm)3. The up and down-quark masses are varied so the pion mass lies between 0.33 and 0.67 GeV while the strange quark mass is about 12% heavier than the physical one. We calculate the form factors in the range of momentum transfers, 0.2<q2<0.75GeV2. The vector and induced tensor form factors are well described by the conventional dipole forms and result in significant underestimation of the Dirac and Pauli mean-squared radii and the anomalous magnetic moment compared to the respective experimental values. We show that the axial-vector form factor is significantly affected by the finite spatial volume of the lattice. In particular in the axial charge, gA/gV, the finite-volume effect scales with a single dimensionless quantity, mπL, the product of the calculated pion mass and the spatial lattice extent. Our results indicate that for this quantity, mπL>6 is required to ensure that finite-volume effects are below 1%.

Original languageEnglish
Article number114505
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume79
Issue number11
DOIs
Publication statusPublished - 2009 Jun 29
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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