Document Type

Article

Department/Program

Physics

Journal Title

Physics Letters B

Pub Date

5-2015

Publisher

Elsevier

Volume

744

First Page

309

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

We have performed precision measurements of the double-spin virtual-photon asymmetry A1 on the neutron in the deep inelastic scattering regime, using an open-geometry, large-acceptance spectrometer and a longitudinally and transversely polarized 3He target. Our data cover a wide kinematic range 0.277 ≤ x ≤ 0.548 at an average Q 2 value of 3.078 (GeV/c)2, doubling the available high-precision neutron data in this x range. We have combined our results with world data on proton targets to make a leading-order extraction of the ratio of polarized-to-unpolarized parton distribution functions for up quarks and for down quarks in the same kinematic range. Our data are consistent with a previous observation of an An 1 zero crossing near x = 0.5. We find no evidence of a transition to a positive slope in (d + ¯ d)/(d + ¯ d) up to x = 0.548

DOI

https://doi.org/10.1016/j.physletb.2015.03.067

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