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DOE OSTI · 1604453

Sivers function in the quasiclassical approximation

Kovchegov, Yuri V.·Sievert, Matthew D.
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Abstract

In this study, we calculate the Sivers function in semi-inclusive deep inelastic scattering (SIDIS) and in the Drell-Yan process (DY) by employing the quasiclassical Glauber-Mueller/McLerran-Venugopalan approximation. Modeling the hadron as a large “nucleus” with nonzero orbital angular momentum (OAM), we find that its Sivers function receives two dominant contributions: one contribution is due to the OAM, while another one is due to the local Sivers function density in the nucleus. While the latter mechanism, being due to the “lensing” interactions, dominates at large transverse momentum of the produced hadron in SIDIS or of the dilepton pair in DY, the former (OAM) mechanism is leading in saturation power counting and dominates when the above transverse momenta become of the order of the saturation scale. We show that the OAM channel allows for a particularly simple and intuitive interpretation of the celebrated sign flip between the Sivers functions in SIDIS and DY.

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BibTeXRIS

Kovchegov, Yuri V., Sievert, Matthew D.. 2014-03-26. Sivers function in the quasiclassical approximation. https://doi.org/10.1103/physrevd.89.054035

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