Poincaré subalgebra and gauge invariance in nucleon structure

Xiang-Song Chen

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arXiv · 1203.1288

Poincaré subalgebra and gauge invariance in nucleon structure

Xiang-Song Chen

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Abstract

By separating the gluon field into physical and pure-gauge components, the usual Poincaré subalgebra for an interacting system can be reconciled with gauge-invariance when decomposing the total rotation and translation generators of QCD into quark and gluon parts. The gauge-invariant quark/gluon parts act as the generators for the gauge-invariant physical component of the quark/gluon field, not the full quark/gluon field which also contains the gauge degrees of freedom. We clarify that the naive canonical decomposition of generators, while trivially respecting the Poincaré subalgebra, might not give a completely gauge-invariant quark-gluon structure of the nucleon momentum and spin, though limited invariance within a certain gauge class can be proven.

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Xiang-Song Chen. 2012-03-06. Poincaré subalgebra and gauge invariance in nucleon structure. https://arxiv.org/abs/1203.1288

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