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arXiv · 1904.02287

New approach to the Sivers effect in the collinear twist-3 formalism

Hongxi Xing·Shinsuke Yoshida
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Abstract

The single-transverse spin asymmetry(SSA) for hadron production in the transversely polarized proton scattering receives major contribution from Sivers effect, which can be systematically described within the collinear twist-3 factorization framework in various processes. Conventional method in the evaluation of the Sivers effect known as pole calculation is technically quite different from non-pole calculation which is another method used in evaluating the final state twist-3 effect. In this paper, we extend the non-pole technique to the Sivers effect, and show the consistency with the conventional method through an explicit calculation of $\mathcal{O}(α_s)$ correction in semi-inclusive deep inelastic scattering. As a result, we clarify that the conventional pole calculation is implicitly using the equation of motion and the Lorentz invariant relations whose importance became widely known in the non-pole calculation. We also clarify some technical advantages in using the new non-pole method.

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Hongxi Xing, Shinsuke Yoshida. 2019-09-04. New approach to the Sivers effect in the collinear twist-3 formalism. https://doi.org/10.1103/physrevd.100.054024

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