Physics of the Gluon-Helicity Contribution to Proton Spin
Abstract
The total gluon helicity in a polarized proton, measurable in high-energy scattering, is shown to be the large momentum limit of a gauge-invariant but nonlocal, frame-dependent gluon spin E→×A→⊥ in QCD. This opens a door for a nonperturbative calculation of this quantity in lattice QCD and also justifies using free-field expressions in the light-cone gauge as physical observables.
- Publication:
-
Physical Review Letters
- Pub Date:
- September 2013
- DOI:
- 10.1103/PhysRevLett.111.112002
- arXiv:
- arXiv:1304.6708
- Bibcode:
- 2013PhRvL.111k2002J
- Keywords:
-
- 14.20.Dh;
- 12.38.Gc;
- 13.88.+e;
- 14.70.Dj;
- Protons and neutrons;
- Lattice QCD calculations;
- Polarization in interactions and scattering;
- Gluons;
- High Energy Physics - Phenomenology
- E-Print:
- 7 pages, 1 figure