Axialvector form factors of the nucleon from lattice QCD
Abstract
In this paper, we present results for the form factors of the isovector axial vector current in the nucleon state using large scale simulations of lattice QCD. The calculations were done using eight ensembles of gauge configurations generated by the MILC collaboration using the HISQ action with 2 + 1 + 1 dynamical flavors. These ensembles span three lattice spacings a ≈ 0.06 , 0.09, and 0.12 fm and lightquark masses corresponding to the pion masses M _{π} ≈ 135, 225, and 310 MeV. Highstatistics estimates allow us to quantify systematic uncertainties in the extraction of G _{A} (Q ^{2}) and the induced pseudoscalar form factor G _{P}(Q ^{2}) . We perform a simultaneous extrapolation in the lattice spacing, lattice volume and lightquark masses of the axial charge radius r _{A} data to obtain physical estimates. Using the dipole ansatz to fit the Q ^{2} behavior we obtain r _{A}  _{dipole} = 0.49(3) fm , which corresponds to M _{A} = 1.39(9) GeV , and is consistent with M _{A} = 1.35(17) GeV obtained by the miniBooNE collaboration. The estimate obtained using the z expansion is r _{A}  _{z  expansion} = 0.46(6) fm, and the combined resultmore »
 Authors:
 Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
 Michigan State Univ., East Lansing, MI (United States)
 Publication Date:
 Research Org.:
 Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
 Sponsoring Org.:
 USDOE Office of Science (SC), High Energy Physics (HEP) (SC25); USDOE Laboratory Directed Research and Development (LDRD) Program
 OSTI Identifier:
 1415378
 Report Number(s):
 LAUR1723678
Journal ID: ISSN 24700010; PRVDAQ
 Grant/Contract Number:
 AC5206NA25396; AC0205CH11231; KA1401020
 Resource Type:
 Journal Article: Accepted Manuscript
 Journal Name:
 Physical Review D
 Additional Journal Information:
 Journal Volume: 96; Journal Issue: 11; Journal ID: ISSN 24700010
 Publisher:
 American Physical Society (APS)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Axial form factors; nucleons; lattice QCD
Citation Formats
Gupta, Rajan, Jang, YongChull, Lin, HueyWen, Yoon, Boram, and Bhattacharya, Tanmoy. Axialvector form factors of the nucleon from lattice QCD. United States: N. p., 2017.
Web. doi:10.1103/PhysRevD.96.114503.
Gupta, Rajan, Jang, YongChull, Lin, HueyWen, Yoon, Boram, & Bhattacharya, Tanmoy. Axialvector form factors of the nucleon from lattice QCD. United States. doi:10.1103/PhysRevD.96.114503.
Gupta, Rajan, Jang, YongChull, Lin, HueyWen, Yoon, Boram, and Bhattacharya, Tanmoy. 2017.
"Axialvector form factors of the nucleon from lattice QCD". United States.
doi:10.1103/PhysRevD.96.114503.
@article{osti_1415378,
title = {Axialvector form factors of the nucleon from lattice QCD},
author = {Gupta, Rajan and Jang, YongChull and Lin, HueyWen and Yoon, Boram and Bhattacharya, Tanmoy},
abstractNote = {In this paper, we present results for the form factors of the isovector axial vector current in the nucleon state using large scale simulations of lattice QCD. The calculations were done using eight ensembles of gauge configurations generated by the MILC collaboration using the HISQ action with 2 + 1 + 1 dynamical flavors. These ensembles span three lattice spacings a ≈ 0.06 , 0.09, and 0.12 fm and lightquark masses corresponding to the pion masses Mπ ≈ 135, 225, and 310 MeV. Highstatistics estimates allow us to quantify systematic uncertainties in the extraction of GA (Q2) and the induced pseudoscalar form factor GP(Q2) . We perform a simultaneous extrapolation in the lattice spacing, lattice volume and lightquark masses of the axial charge radius rA data to obtain physical estimates. Using the dipole ansatz to fit the Q2 behavior we obtain rA dipole = 0.49(3) fm , which corresponds to MA = 1.39(9) GeV , and is consistent with MA = 1.35(17) GeV obtained by the miniBooNE collaboration. The estimate obtained using the z expansion is rA z  expansion = 0.46(6) fm, and the combined result is rA  combined = 0.48(4) fm. Analysis of the induced pseudoscalar form factor GP (Q2) yields low estimates for g*P and gπNN compared to their phenomenological values. To understand these, we analyze the partially conserved axial current (PCAC) relation by also calculating the pseudoscalar form factor. Lastly, we find that these low values are due to large deviations in the PCAC relation between the three form factors, and in the pionpole dominance hypothesis.},
doi = {10.1103/PhysRevD.96.114503},
journal = {Physical Review D},
number = 11,
volume = 96,
place = {United States},
year = 2017,
month =
}

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