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arXiv · 0903.1923

Soft-fermion-pole contribution to single-spin asymmetry for pion production in pp collisions

Yuji Koike·Tetsuya Tomita
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Abstract

We study the single transverse spin asymmetry for the inclusive pion production in the nucleon-nucleon collision, p^\uparrow p\toπX, based on the twist-3 mechanism in the collinear factorization. We derive the soft-fermion-pole (SFP) contribution to the twist-3 single-spin-dependent cross section associated with the twist-3 quark-gluon correlation functions in the polarized nucleon. We find that the SFP can give rise to a large effect to the asymmetry A_N owing to the large partonic hard cross sections with the large color factor, if the SFP function has a similar magnitude as the soft-gluon-pole (SGP) function, in spite of the absence of the "derivative term" for the SFP function unlike for the SGP function.

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Yuji Koike, Tetsuya Tomita. 2009-04-07. Soft-fermion-pole contribution to single-spin asymmetry for pion production in pp collisions. https://doi.org/10.1016/j.physletb.2009.04.017

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