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DOE OSTI · 1345044

QCD and Standard Model Studies

Gagliardi, Carl A
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Abstract

Our group has focused on using jets in STAR to investigate the longitudinal and transverse spin structure of the proton. We performed measurements of the longitudinal double-spin asymmetry for inclusive jet production that provide the strongest evidence to date that the gluons in the proton with x>0.05 are polarized. We also made the first observation of the Collins effect in pp collisions, thereby providing an important test of the universality of the Collins fragmentation function and opening a new tool to probe quark transversity in the proton. Our studies of forward rapidity electromagnetic jet-like events raise serious question whether the large transverse spin asymmetries that have been seen for forward inclusive hadron production arise from conventional 2 → 2 parton scattering. This is the final technical report for DOE Grant DE-FG02-93ER40765. It covers activities during the period January 1, 2015 through November 30, 2016.

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72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDSCollins effectgluon polarizationProton spintransverse single-spin asymmetries

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Gagliardi, Carl A. 2017-02-28. QCD and Standard Model Studies. https://doi.org/10.2172/1345044

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