Physics Letters B
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 Q2 value of 3.078(GeV/c)2, doubling the available high-precision neutron data in this xrange. 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 An1zero crossing near x = 0.5. We find no evidence of a transition to a positive slope in (Δd + Δ¯d)/(d +¯d) up to x = 0.548.
Original Publication Citation
Parno, D. S., Flay, D., Posik, M., Allada, K., Armstrong, W., Averett, T., . . . Zheng, X. (2015). Precision measurements of Aⁿ1 in the deep inelastic regime. Physics Letters B, 744, 309-314. doi:10.1016/j.physletb.2015.03.067
Parno, D. S.; Flay, D.; Posik, M.; Canan, M.; Hyde, C.; and The Jefferson Lab Hall A Collaboration, "Precision Measurements of Aⁿ1 in the Deep Inelastic Regime" (2015). Physics Faculty Publications. 149.