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Precision measurements of A^n_1 in the deep inelastic regime

Parno, D. S. and Qian, X. (2015) Precision measurements of A^n_1 in the deep inelastic regime. Physics Letters B, 744 . pp. 309-314. ISSN 0370-2693.

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We have performed precision measurements of the double-spin virtual-photon asymmetry A_1 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 A_1^n zero crossing near x=0.5. We find no evidence of a transition to a positive slope in (Δd+Δd)/(d+d) up to x=0.548x=0.548.

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Additional Information:© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license ( Funded by SCOAP3. We gratefully acknowledge the outstanding support of the Jefferson Lab Accelerator Division and Hall A staff in bringing this experiment to a successful conclusion. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award Numbers DE-FG02-87ER40315 and DE-FG02-94ER40844 and Contract DE-AC05-06OR23177, under which the Jefferson Science Associates, LLC, operate Jefferson Lab.
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-87ER40315
Department of Energy (DOE)DE-FG02-94ER40844
Department of Energy (DOE)DE-AC05-06OR23177
Subject Keywords:Spin structure functions; Nucleon structure; Parton distribution functions; Polarized electron scattering
Record Number:CaltechAUTHORS:20150603-081600016
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Official Citation:The Jefferson Lab Hall A Collaboration, Precision measurements of in the deep inelastic regime, Physics Letters B, Volume 744, 11 May 2015, Pages 309-314, ISSN 0370-2693, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57964
Deposited By: Ruth Sustaita
Deposited On:03 Jun 2015 17:29
Last Modified:03 Oct 2019 08:30

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