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Phys. Rev. D 64, 052002 (2001) [16 pages]

Improved measurement of the d̅ /ū asymmetry in the nucleon sea

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R. S. Towell et al. (FNAL E866/NuSea Collaboration)
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Received 14 March 2001; published 10 August 2001

Measurements of the ratio of Drell-Yan yields from an 800 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 down antiquark (d̅ ) to up (ū) antiquark 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, (d̅ -ū) and ∫(d̅ -ū)dx are evaluated for 0.015<x<0.35. These results are compared with parametrizations of various parton distribution functions, models and experimental results from NA51, NMC and HERMES.


©2001 The American Physical Society

URL: http://link.aps.org/doi/10.1103/PhysRevD.64.052002
DOI: 10.1103/PhysRevD.64.052002
PACS: 13.85.Qk, 14.20.Dh, 14.65.Bt, 24.85.+p

* Present address: University of Illinois at Urbana-Champaign, Urbana, IL 61801.
† Present address: Florida State University, Tallahassee, FL 32306.
‡ On leave from Kurchatov Institute, Moscow 123182, Russia.

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