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arXiv · 0905.1033

Recent STAR Results from Charged Pion Production in Polarized pp Collisions at $\sqrt{s} = 200 GeV$ at RHIC

Adam Kocoloski
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Abstract

The STAR experiment at RHIC measures the longitudinal double-spin asymmetry $A_{LL}$ for a variety of final states in collisions of longitudinally polarized protons to constrain the polarized gluon distribution in the proton. Asymmetries for mid-rapidity charged pion production benefit from large cross-sections and the excellent tracking and particle identification capabilities of the STAR Time Projection Chamber. This contribution presents a measurement of the ratio of cross sections for inclusive $\pi^{-}$ and $\pi^{+}$ production using data collected in 2005, as well as a new measurement of $A_{LL}$ for charged pions opposite a jet obtained from the 2006 RHIC run.

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Adam Kocoloski. 2009-05-07. Recent STAR Results from Charged Pion Production in Polarized pp Collisions at $\sqrt{s} = 200 GeV$ at RHIC. https://doi.org/10.1063/1.3215645

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