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Improved Measurement of the $\bar d / \bar u$ Asymmetry in the Nucleon Sea

NuSea Collaboration·R. S. Towell·P. L. McGaughey
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Abstract

Measurements of the ratio of Drell-Yan yields from an 800 \rm{GeV/c} proton beam incident on liquid hydrogen and deuterium targets are reported. Approximately 360,000 Drell-Yan muon pairs remained after all cuts on the data. From these data, the ratio of anti-down ($\bar{d}$) to anti-up ($\bar{u}$) quark distributions in the proton sea is determined over a wide range in Bjorken-$x$. These results confirm previous measurements by E866 and extend them to lower $x$. From these data, $(\bar{d}-\bar{u})$ and $\int(\bar{d}-\bar{u})dx$ are evaluated for $0.015<x<0.35$. These results are compared with parameterizations of various parton distribution functions, models and experimental results from NA51, NMC, and HERMES.

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NuSea Collaboration, R. S. Towell, P. L. McGaughey. 2001-03-20. Improved Measurement of the $\bar d / \bar u$ Asymmetry in the Nucleon Sea. https://doi.org/10.1103/physrevd.64.052002

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