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arXiv · hep-ph/0606238

Instanton contribution to the Sivers function

I. O. Cherednikov·U. D'Alesio·N. I. Kochelev·F. Murgia
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Abstract

We study the Sivers function for valence u and d quarks in the proton within the instanton model for QCD vacuum, adopting the MIT bag model wave functions for quarks. Within approaches based on perturbative one-gluon final state interactions a non-zero value of the Sivers function is related to the presence of both S and P wave components in quark wave functions. We show that the instanton-induced chromomagnetic, nonperturbative interaction leads to very specific spin-spin correlations between the struck and spectator quarks, resulting in a non-trivial flavour dependence of the Sivers function. Comparison of the obtained Sivers functions with phenomenological parameterizations is discussed.

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I. O. Cherednikov, U. D'Alesio, N. I. Kochelev, F. Murgia. 2006-10-10. Instanton contribution to the Sivers function. https://doi.org/10.1016/j.physletb.2006.09.019

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