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Transverse Spin / Transverse Momentum Analogy and Gauge Invariance of Deeply Virtual Compton Scattering

B. Pire·O. V. Teryaev
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Abstract

Using the similarity between twist 3 contributions to transverse spin for usual parton distributions and transverse momentum for non-diagonal parton distributions, we determine for the simple case of a scalar (pion, $He^4$) target the linear in transverse momentum twist-3 contribution to Deeply Virtual Compton amplitude. This allows to write a gauge invariant amplitude for this non-forward process.

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B. Pire, O. V. Teryaev. 1999-04-20. Transverse Spin / Transverse Momentum Analogy and Gauge Invariance of Deeply Virtual Compton Scattering. https://arxiv.org/abs/hep-ph/9904375

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