Quark and Glue Components of the Proton Spin from Lattice Calculation

2015/04/30 by Keh-Fei Liu
Physics and Astronomy · #Angular momentum #Angular momentum coupling #Fermion #GLUE #High-Energy Particle Collisions Research #Lattice (music) #Nuclear physics #Nucleon #Particle physics #Particle physics theoretical and experimental studies #Physics #Proton #Proton spin crisis #Quantum Chromodynamics and Particle Interactions #Quantum mechanics #Quark #Spin (aerodynamics) #Total angular momentum quantum number #hep-lat #hep-ph #nucl-th

paper · pdf · doi:10.1142/s2010194516600053

Plenary talk presented at SPIN2014, the 21st International Symposium on Spin Physics, 16 pages, 6 figures, references added and typos corrected. arXiv admin note: text overlap with arXiv:1504.04052

arxiv created 2015/05/28 · openalex publication_date 2016/01/01 · arxiv updated 2016/03/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

The status of lattice calculations of the quark spin, the quark orbital angular momentum, the glue angular momentum and glue spin in the nucleon is summarized. The quark spin calculation is recently carried out from the anomalous Ward identity with chiral fermions and is found to be small mainly due to the large negative anomaly term which is believed to be the source of the ‘proton spin crisis’. We also present the first calculation of the glue spin at finite nucleon momenta.

Citations

• Quark Spin in Proton from Anomalous Ward Indentity
• The RHIC SPIN Program: Achievements and Future Opportunities
• Quark Contributions to Nucleon Momentum and Spin from Domain Wall fermion calculations
• Glue Spin S_G in The Longitudinally Polarized Nucleon
• Evidence for the absence of gluon orbital angular momentum in the nucleon
• Classical limits of scalar and tensor gauge operators based on the overlap Dirac matrix