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arXiv · 1202.2843

Proton Spin Structure from Measurable Parton Distributions

Xiangdong Ji·Xiaonu Xiong·Feng Yuan
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Abstract

We present a systematic study of the proton spin structure in terms of measurable parton distributions. For a transversely-polarizedproton, we derive a polarization sum rule from the leading generalized parton distributions appearing in hard exclusive processes. For a longitudinally-polarized proton, we obtain a helicity decomposition from well-known quark and gluon helicity distributions and orbital angular-momentum contributions. The latter is shown to be related to measurable subleading generalized parton distributions and quantum-phase space Wigner distributions.

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Xiangdong Ji, Xiaonu Xiong, Feng Yuan. 2012-10-17. Proton Spin Structure from Measurable Parton Distributions. https://doi.org/10.1103/physrevlett.109.152005

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