Angular momentum conservation law in lightfront quantum field theory
Abstract
We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the lightfront formulation. We explicitly show that j ^{3}, the z component of the angular momentum remains unchanged under Lorentz transformations generated by the lightfront kinematical boost operators. The invariance of j ^{3} under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED and QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.
 Authors:
 SLAC National Accelerator Lab., Menlo Park, CA (United States)
 Publication Date:
 Research Org.:
 SLAC National Accelerator Lab., Menlo Park, CA (United States)
 Sponsoring Org.:
 USDOE
 OSTI Identifier:
 1360755
 Alternate Identifier(s):
 OSTI ID: 1349545
 Grant/Contract Number:
 AC0276SF00515
 Resource Type:
 Journal Article: Accepted Manuscript
 Journal Name:
 Physical Review D
 Additional Journal Information:
 Journal Volume: 95; Journal Issue: 6; Journal ID: ISSN 24700010
 Publisher:
 American Physical Society (APS)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
Citation Formats
Chiu, Kelly YuJu, and Brodsky, Stanley J. Angular momentum conservation law in lightfront quantum field theory. United States: N. p., 2017.
Web. doi:10.1103/PhysRevD.95.065035.
Chiu, Kelly YuJu, & Brodsky, Stanley J. Angular momentum conservation law in lightfront quantum field theory. United States. doi:10.1103/PhysRevD.95.065035.
Chiu, Kelly YuJu, and Brodsky, Stanley J. Fri .
"Angular momentum conservation law in lightfront quantum field theory". United States.
doi:10.1103/PhysRevD.95.065035. https://www.osti.gov/servlets/purl/1360755.
@article{osti_1360755,
title = {Angular momentum conservation law in lightfront quantum field theory},
author = {Chiu, Kelly YuJu and Brodsky, Stanley J.},
abstractNote = {We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the lightfront formulation. We explicitly show that j3, the z component of the angular momentum remains unchanged under Lorentz transformations generated by the lightfront kinematical boost operators. The invariance of j3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED and QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.},
doi = {10.1103/PhysRevD.95.065035},
journal = {Physical Review D},
number = 6,
volume = 95,
place = {United States},
year = {Fri Mar 31 00:00:00 EDT 2017},
month = {Fri Mar 31 00:00:00 EDT 2017}
}
Web of Science

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the lightfront formulation. We explicitly show that j 3 , the z component of the angular momentum remains unchanged under Lorentz transformations generated by the lightfront kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QEDmore »

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