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arXiv · 0901.3601

Drell-Yan Lepton Pair Azimuthal Asymmetry in Hadronic Processes

Jian Zhou·Feng Yuan·Zuo-tang Liang
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Abstract

We study the azimuthal asymmetry in the Drell-Yan lepton pair production in hadronic scattering processes at moderate transverse momentum region, taking into account the contributions from the twist-three quark-gluon correlations from the unpolarized hadrons. The contributions are found to dominate the asymmetry, and are not power suppressed by q_\perp/Q at small q_\perp where q_\perp and Q are the transverse momentum and invariant mass of the lepton pair. Accordingly, the Lam-Tung relation will be violated at this momentum region, and its violation depends on the twist-three functions. However, at large transverse momentum q_\perp\sim Q, the Lam-Tung relation still holds because all corrections are power suppressed by Λ^2/q_\perp^2\sim Λ^2/Q^2 where Λis the typical nonperturbative scale.

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Jian Zhou, Feng Yuan, Zuo-tang Liang. 2009-01-23. Drell-Yan Lepton Pair Azimuthal Asymmetry in Hadronic Processes. https://doi.org/10.1016/j.physletb.2009.06.041

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