Title: Strange and charm quark spins from the anomalous Ward identity

Abstract

In this article, we present a calculation of the strange and charm quark contributions to the nucleon spin from the anomalous Ward identity (AWI). This is performed with overlap valence quarks on $2+1$-flavor domain-wall fermion gauge configurations on a $24^3\times 64$ lattice with lattice spacing $a^{-1}=1.73\mathrm{GeV}$ and the light sea mass at $m_{\pi }=330\mathrm{MeV}$. To satisfy the AWI, the overlap fermion for the pseudoscalar density and the overlap Dirac operator for the topological density, which do not have multiplicative renormalization, are used to normalize the form factor of the local axial-vector current at finite $q^2$. For the charm quark, we find that the negative pseudoscalar term almost cancels the positive topological term. For the strange quark, the pseudoscalar term is less negative than that of the charm. By imposing the AWI, the strange $g_A\left(q^2\right)$ at $q^2=0$ is obtained by a global fit of the pseudoscalar and the topological form factors, together with $g_A\left(q^2\right)$ and the induced pseudoscalar form factor $h_A\left(q^2\right)$ at finite $q^2$. The chiral extrapolation to the physical pion mass gives $\mathrm{\Delta }s+\mathrm{\Delta }\overline{s}=-0.0403\left(44\right)\left(78\right)$.

Authors:

Gong, Ming  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-3761-5928"

Yang, Yi-Bo  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-3213-0438"

Liang, Jian ^[2]; Alexandru, Andrei  ^[3];

• Search DOE PAGES for author "Alexandru, Andrei"
• Search DOE PAGES for ORCID "0000-0003-4547-1554"

Draper, Terrence ^[2]; Liu, Keh-Fei  ^[2]

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• Search DOE PAGES for ORCID "0000-0002-8943-8011"

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+ Show Author Affiliations

1. Chinese Academy of Sciences (CAS), Beijing (China). Inst. of High Energy Physics
2. University of Kentucky, Lexington, KY (United States)
3. The George Washington University, Washington, DC (United States)

Publication Date:

Thu Jun 22 00:00:00 EDT 2017

Research Org.:

Univ. of Kentucky, Lexington, KY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Nuclear Physics (NP); National Science Foundation of China (NSFC); National Science Foundation (NSF)

Contributing Org.:

χQCD Collaboration

OSTI Identifier:

1599053

Alternate Identifier(s):

OSTI ID: 1365604

Report Number(s):

DOE-UKY-13065-1511.03671
Journal ID: ISSN 2470-0010; PRVDAQ; arXiv:1511.03671; TRN: US2103418

Grant/Contract Number:  

SC0013065; FG02-95ER40907; AC05-00OR22725; 11405178; PHY-1151648; ACI-1053575

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review D

Additional Journal Information:

Journal Volume: 95; Journal Issue: 11; Journal ID: ISSN 2470-0010

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Lattice QCD; Charm quark; Strange quark; Flavor symmetries