2007/06/15 by F. Simon, Simon, Frank
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.0706.2388
openalex publication_date 2007/06/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present measurements of the double longitudinal spin asymmetries for\ninclusive pi0 and pi+(-) production in polarized p+p collisions at sqrt(s) =\n200 GeV at mid-rapidity with the STAR detector from the 2005 RHIC run. These\nmeasurements are used to access Delta G/G, the gluon polarization in the\nproton. The observed unpolarized inclusive cross sections show good agreement\nwith NLO pQCD calculations. The double longitudinal spin asymmetries are\ncompared to NLO pQCD calculations based on different assumptions for the gluon\npolarization in the nucleon to provide constraints on Delta G/G. At the present\nlevel of statistics the measured asymmetries disfavor a large positive gluon\npolarization, but cannot yet distinguish between other scenarios.\n