Isovector axial form factors of the nucleon in two-flavor lattice QCD

Capitani Stefano, Michele Della Morte, Dalibor Djukanovic, G. von Hippel, J. Hua, Benjamin Jager, Junnarkar, H Meyer, Thomas Rae, Hartmut Wittig

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

We present a lattice calculation of the nucleon isovector axial and induced pseudoscalar form factors on the CLS ensembles using Nf = 2 dynamical flavors of nonperturbatively (a)-improved Wilson fermions and an (a)-improved axial current together with the pseudoscalar density. Excited-state effects in the extraction of the form factors are treated using a variety of methods, with a detailed discussion of their respective merits. The chiral and continuum extrapolation of the results is performed both using formulae inspired by Heavy Baryon Chiral Perturbation Theory (HBChPT) and a global approach to the form factors based on a chiral effective field theory (EFT) including axial vector mesons. Our results indicate that careful treatment of excited-state effects is important in order to obtain reliable results for the axial form factors of the nucleon, and that the main remaining error stems from the systematic uncertainties of the chiral extrapolation. As final results, we quote gA = 1.278 ± 0.068- 0.087 +0.000 , (rA2) = 0.360 ± 0.036 -0.088 +0.080 fm 2 , and gP = 7.7 ± 1.8 -2.0 +0.8 for the axial charge, axial charge radius and induced pseudoscalar charge, respectively, where the first error is statistical and the second is systematic.

OriginalsprogEngelsk
Artikelnummer1950009
TidsskriftInternational Journal of Modern Physics A (IJMPA)
Vol/bind34
Udgave nummer2
Antal sider27
ISSN0217-751X
DOI
StatusUdgivet - 2019

Fingeraftryk

form factors
quantum chromodynamics
extrapolation
vector mesons
stems
excitation
baryons
perturbation theory
fermions
continuums
radii

Citer dette

Stefano, Capitani ; Della Morte, Michele ; Djukanovic, Dalibor ; von Hippel, G. ; Hua, J. ; Jager, Benjamin ; Junnarkar ; Meyer, H ; Rae, Thomas ; Wittig, Hartmut. / Isovector axial form factors of the nucleon in two-flavor lattice QCD. I: International Journal of Modern Physics A (IJMPA). 2019 ; Bind 34, Nr. 2.
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title = "Isovector axial form factors of the nucleon in two-flavor lattice QCD",
abstract = "We present a lattice calculation of the nucleon isovector axial and induced pseudoscalar form factors on the CLS ensembles using Nf = 2 dynamical flavors of nonperturbatively (a)-improved Wilson fermions and an (a)-improved axial current together with the pseudoscalar density. Excited-state effects in the extraction of the form factors are treated using a variety of methods, with a detailed discussion of their respective merits. The chiral and continuum extrapolation of the results is performed both using formulae inspired by Heavy Baryon Chiral Perturbation Theory (HBChPT) and a global approach to the form factors based on a chiral effective field theory (EFT) including axial vector mesons. Our results indicate that careful treatment of excited-state effects is important in order to obtain reliable results for the axial form factors of the nucleon, and that the main remaining error stems from the systematic uncertainties of the chiral extrapolation. As final results, we quote gA = 1.278 ± 0.068- 0.087 +0.000 , (rA2) = 0.360 ± 0.036 -0.088 +0.080 fm 2 , and gP = 7.7 ± 1.8 -2.0 +0.8 for the axial charge, axial charge radius and induced pseudoscalar charge, respectively, where the first error is statistical and the second is systematic.",
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year = "2019",
doi = "10.1142/S0217751X1950009X",
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Stefano, C, Della Morte, M, Djukanovic, D, von Hippel, G, Hua, J, Jager, B, Junnarkar, Meyer, H, Rae, T & Wittig, H 2019, 'Isovector axial form factors of the nucleon in two-flavor lattice QCD', International Journal of Modern Physics A (IJMPA), bind 34, nr. 2, 1950009. https://doi.org/10.1142/S0217751X1950009X

Isovector axial form factors of the nucleon in two-flavor lattice QCD. / Stefano, Capitani; Della Morte, Michele ; Djukanovic, Dalibor; von Hippel, G.; Hua, J.; Jager, Benjamin; Junnarkar; Meyer, H; Rae, Thomas; Wittig, Hartmut.

I: International Journal of Modern Physics A (IJMPA), Bind 34, Nr. 2, 1950009, 2019.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Isovector axial form factors of the nucleon in two-flavor lattice QCD

AU - Stefano, Capitani

AU - Della Morte, Michele

AU - Djukanovic, Dalibor

AU - von Hippel, G.

AU - Hua, J.

AU - Jager, Benjamin

AU - Junnarkar, null

AU - Meyer, H

AU - Rae, Thomas

AU - Wittig, Hartmut

PY - 2019

Y1 - 2019

N2 - We present a lattice calculation of the nucleon isovector axial and induced pseudoscalar form factors on the CLS ensembles using Nf = 2 dynamical flavors of nonperturbatively (a)-improved Wilson fermions and an (a)-improved axial current together with the pseudoscalar density. Excited-state effects in the extraction of the form factors are treated using a variety of methods, with a detailed discussion of their respective merits. The chiral and continuum extrapolation of the results is performed both using formulae inspired by Heavy Baryon Chiral Perturbation Theory (HBChPT) and a global approach to the form factors based on a chiral effective field theory (EFT) including axial vector mesons. Our results indicate that careful treatment of excited-state effects is important in order to obtain reliable results for the axial form factors of the nucleon, and that the main remaining error stems from the systematic uncertainties of the chiral extrapolation. As final results, we quote gA = 1.278 ± 0.068- 0.087 +0.000 , (rA2) = 0.360 ± 0.036 -0.088 +0.080 fm 2 , and gP = 7.7 ± 1.8 -2.0 +0.8 for the axial charge, axial charge radius and induced pseudoscalar charge, respectively, where the first error is statistical and the second is systematic.

AB - We present a lattice calculation of the nucleon isovector axial and induced pseudoscalar form factors on the CLS ensembles using Nf = 2 dynamical flavors of nonperturbatively (a)-improved Wilson fermions and an (a)-improved axial current together with the pseudoscalar density. Excited-state effects in the extraction of the form factors are treated using a variety of methods, with a detailed discussion of their respective merits. The chiral and continuum extrapolation of the results is performed both using formulae inspired by Heavy Baryon Chiral Perturbation Theory (HBChPT) and a global approach to the form factors based on a chiral effective field theory (EFT) including axial vector mesons. Our results indicate that careful treatment of excited-state effects is important in order to obtain reliable results for the axial form factors of the nucleon, and that the main remaining error stems from the systematic uncertainties of the chiral extrapolation. As final results, we quote gA = 1.278 ± 0.068- 0.087 +0.000 , (rA2) = 0.360 ± 0.036 -0.088 +0.080 fm 2 , and gP = 7.7 ± 1.8 -2.0 +0.8 for the axial charge, axial charge radius and induced pseudoscalar charge, respectively, where the first error is statistical and the second is systematic.

KW - Nucleon form factors

KW - lattice QCD

KW - nucleon axial charge

U2 - 10.1142/S0217751X1950009X

DO - 10.1142/S0217751X1950009X

M3 - Journal article

VL - 34

JO - International Journal of Modern Physics A

JF - International Journal of Modern Physics A

SN - 0217-751X

IS - 2

M1 - 1950009

ER -