Justifying the naive partonic sum rule for proton spin

Journal Article · Wed Apr 01 00:00:00 EDT 2015 · Physics Letters B

DOI:https://doi.org/10.1016/j.physletb.2015.02.054· OSTI ID:1228402

Ji, Xiangdong; Zhang, Jian-Hui; Zhao, Yong

We provide a theoretical basis for understanding the spin structure of the proton in terms of the spin and orbital angular momenta of free quarks and gluons in Feynman’s parton picture. We show that each term in the Jaffe–Manohar spin sum rule can be related to the matrix element of a gauge-invariant, but frame-dependent operator through a matching formula in large-momentum effective field theory. We present all the matching conditions for the spin content at one-loop order in perturbation theory, which provide a basis to calculate parton orbital angular momentum in lattice QCD at leading logarithmic accuracy.

• Research Organization: Univ. of Maryland, College Park, MD (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: FG02-93ER-40762; 11DZ2260700; 11175114; 11405104
• OSTI ID: 1228402
• Alternate ID(s): OSTI ID: 1184808
• Journal Information: Physics Letters B, Journal Name: Physics Letters B Vol. 743 Journal Issue: C; ISSN 0370-2693
• Publisher: Elsevier
• Country of Publication: Netherlands
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS