The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8<ηpT/c and is found to agree with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry ALL is measured in the same pseudorapidity range and spans a range of Bjorken-x down to x≈0.01. The measured ALL is consistent with model predictions for varying degrees of gluon polarization. The parity-violating asymmetry AL is also measured and found to be consistent with zero. The transverse single-spin asymmetry AN is measured over a previously unexplored kinematic range in Feynman-x and pT. Such measurements may aid our understanding of the onset and kinematic dependence of the large asymmetries observed at more forward pseudorapidity (η≈3) and their underlying mechanisms. The AN results presented are consistent with a twist-3 model prediction of a small asymmetry over the present kinematic range.

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Published in Physical Review D: Particles, Fields, Gravitation and Cosmology, v. 89, article 012001, p. 1-11.

© 2014 American Physical Society

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Due to the large number of authors involved, only the first 10 and the ones affiliated with the University of Kentucky are listed in the author section above. The authors of this article are collectively known as STAR Collaboration.

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