Proton momentum and angular momentum decompositions with overlap fermions

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We present a calculation of the proton momentum and angular momentum decompositions using overlap fermions on a 2+1-flavor RBC/UKQCD domain-wall lattice at 0.143 fm with a pion mass of 171 MeV which is close to the physical one. A complete determination of the momentum and angular momentum fractions carried by up, down, strange, and glue inside the proton has been done with valence pion masses varying from 171 to 391 MeV. We have utilized fast Fourier transform on the stochastic-sandwich method for connected-insertion parts and the cluster-decomposition error reduction technique technique for disconnected-insertion parts has been used to reduce statistical errors. The full nonperturbative renormalization and mixing between the quark and glue operators are carried out. The final results are normalized with the momentum and angular momentum sum rules and reported at the physical valence pion mass at MS¯(μ=2 GeV). The renormalized momentum fractions for the quarks and glue are xq=0.491(20)(23) and xg=0.509(20)(23), respectively, and the renormalized total angular momentum fractions for quarks and glue are 2Jq=0.539(22)(44) and 2Jg=0.461(22)(44), respectively. The quark spin fraction is ς=0.405(25)(37) from our previous work and the quark orbital angular momentum fraction is deduced from 2Lq=2Jq-ς to be 0.134(22)(44).

Original languageEnglish
Article number014512
JournalPhysical Review D
Issue number1
StatePublished - Jul 1 2022

Bibliographical note

Funding Information:
We thank the RBC/UKQCD Collaborations for providing their domain-wall gauge configurations. This work is supported in part by the U.S. DOE Grant No. DE-SC0013065 and DOE Grant No. DE-AC05-06OR23177 which is within the framework of the TMD Topical Collaboration. Y. Y. is supported by the Strategic Priority Research Program of Chinese Academy of Sciences, Grants No. XDC01040100, No. XDB34030300, and No. XDPB15. Y. Y. is also supported in part by a National Natural Science Foundation of China (NSFC) and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) joint Grant No. 12061131006 and SCHA 458/22. J. L. is supported by the Science and Technology Program of Guangzhou (No. 2019050001). This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. This work used Stampede time under the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation Grant No. ACI-1053575. We also thank the National Energy Research Scientific Computing Center (NERSC) for providing HPC resources that have contributed to the research results reported within this paper. We acknowledge the facilities of the USQCD Collaboration used for this research in part, which are funded by the Office of Science of the U.S. Department of Energy.

Publisher Copyright:
© 2022 authors. Published by the American Physical Society.

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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