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arXiv · 1806.10901

Single spin asymmetries in ultra-peripheral $p^\uparrow A$ collisions

Sanjin Benić·Yoshitaka Hatta
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Abstract

We suggest inclusive hadron production in ultra-peripheral proton-nucleus collisions (UPCs) $p^\uparrow A \to h AX$ as a new channel to investigate single spin asymmetries (SSAs), in particular, to test the assumed dominance of the contribution from twist-three fragmentation functions. The UPC cross sections are obtained by considering the photoproduction limit of semi-inclusive deep inelastic scattering (SIDIS). In particular, we find simple formulas for the polarized UPC cross sections in the collinear twist-three framework. We then numerically calculate the fragmentation contribution to SSA in $p^\uparrow A \to πA X$ at $\sqrt{s} = 200$ GeV and find a few percent asymmetry in the forward region.

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Sanjin Benić, Yoshitaka Hatta. 2018-11-30. Single spin asymmetries in ultra-peripheral $p^\uparrow A$ collisions. https://doi.org/10.1103/physrevd.98.094025

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