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Title: Glue Spin and Helicity in the Proton from Lattice QCD

Authors:
; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1345860
Grant/Contract Number:
SC0013065; FG02-95ER40907; FG02-93ER-40762; AC02-05CH11231; AC05-00OR22725
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 118; Journal Issue: 10; Related Information: CHORUS Timestamp: 2017-04-06 11:05:53; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Yang, Yi-Bo, Sufian, Raza Sabbir, Alexandru, Andrei, Draper, Terrence, Glatzmaier, Michael J., Liu, Keh-Fei, Zhao, Yong, and χQCD Collaboration. Glue Spin and Helicity in the Proton from Lattice QCD. United States: N. p., 2017. Web. doi:10.1103/PhysRevLett.118.102001.
Yang, Yi-Bo, Sufian, Raza Sabbir, Alexandru, Andrei, Draper, Terrence, Glatzmaier, Michael J., Liu, Keh-Fei, Zhao, Yong, & χQCD Collaboration. Glue Spin and Helicity in the Proton from Lattice QCD. United States. doi:10.1103/PhysRevLett.118.102001.
Yang, Yi-Bo, Sufian, Raza Sabbir, Alexandru, Andrei, Draper, Terrence, Glatzmaier, Michael J., Liu, Keh-Fei, Zhao, Yong, and χQCD Collaboration. Mon . "Glue Spin and Helicity in the Proton from Lattice QCD". United States. doi:10.1103/PhysRevLett.118.102001.
@article{osti_1345860,
title = {Glue Spin and Helicity in the Proton from Lattice QCD},
author = {Yang, Yi-Bo and Sufian, Raza Sabbir and Alexandru, Andrei and Draper, Terrence and Glatzmaier, Michael J. and Liu, Keh-Fei and Zhao, Yong and χQCD Collaboration},
abstractNote = {},
doi = {10.1103/PhysRevLett.118.102001},
journal = {Physical Review Letters},
number = 10,
volume = 118,
place = {United States},
year = {Mon Mar 06 00:00:00 EST 2017},
month = {Mon Mar 06 00:00:00 EST 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevLett.118.102001

Citation Metrics:
Cited by: 5works
Citation information provided by
Web of Science

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  • A lattice QCD calculation of the proton matrix element of the flavor singlet axial-vector current is reported. Both the connected and disconnected contributions are calculated, for the latter employing the variant method of wall source without gauge fixing. From simulations in quenched QCD with the Wilson quark action on a 16{sup 3}{times}20 lattice at {beta}=5.7 (the lattice spacing {ital a}{approx}0.14 fm), we find {Delta}{Sigma}={Delta}{ital u}+{Delta}{ital d}+{Delta}{ital s}=+0.638(54){minus}0.347(46){minus}0.109(30)=+0.18(10) with the disconnected contribution to {Delta}{ital u} and {Delta}{ital d} equal to {minus}0.119(44), which is reasonably consistent with the experiment.
  • The double helicity asymmetry in neutral pion production for p{sub T} = 1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, {Delta}G, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of {mu}{sup 2} = 4 GeV{sup 2} a next to leading order QCD analysis gives {Delta}G{sup [0.02,0.3]} = 0.2, with a constraint of -0.7 < {Delta}G{sup [0.02,0.3]} < 0.5 at {Delta}{chi}{sup 2} = 9 ({approx}3{sigma}) for the sampled gluon momentum fraction (x) range, 0.02 to 0.3. The results are obtained using predictions for the measured asymmetries generatedmore » from four representative fits to polarized deep inelastic scattering data. We also consider the dependence of the {Delta}G constraint on the choice of the theoretical scale, a dominant uncertainty in these predictions.« less
  • The double helicity asymmetry in neutral pion production for p{sub T} = 1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, {Delta}G, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of {mu}{sup 2} = 4 GeV{sup 2} a next to leading order QCD analysis gives {Delta}G{sup [0.02,0.3]} = 0.2, with a constraint of -0.7 < {Delta}G{sup [0.02,0.3]} < 0.5 at {Delta}{chi}{sup 2} = 9 (-3{sigma}) for the sampled gluon momentum fraction (x) range, 0.02 to 0.3. The results are obtained using predictions for the measured asymmetries generatedmore » from four representative fits to polarized deep inelastic scattering data. We also consider the dependence of the {Delta}G constraint on the choice of the theoretical scale, a dominant uncertainty in these predictions.« less
  • The double helicity asymmetry in neutral pion production for p{sub T}=1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, DELTAG, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of mu{sup 2}=4 GeV{sup 2} a next to leading order QCD analysis gives DELTAG{sup [0.02,0.3]}=0.2, with a constraint of -0.7<DELTAG{sup [0.02,0.3]}<0.5 at DELTAchi{sup 2}=9 (approx3sigma) for the sampled gluon momentum fraction (x) range, 0.02 to 0.3. The results are obtained using predictions for the measured asymmetries generated from four representative fits to polarized deep inelastic scattering data. We alsomore » consider the dependence of the DELTAG constraint on the choice of the theoretical scale, a dominant uncertainty in these predictions.« less