English

Spin effects in large rapidity pi0 production at STAR

High Energy Physics - Experiment 2019-08-15 v1

Abstract

Measurements by the STAR collaboration of neutral pion production at large Feynman xx (xFx_F) in the first polarized proton collisions at s=200\sqrt{s}=200 GeV were reported previously. During the following two runs additional statistics were acquired with an improved forward calorimeter for the π0\pi^0 cross-section and analyzing power measurements. First data from pppp collisions at s=410\sqrt{s}=410 GeV were taken during the RHIC run that ended in June, 2005. The cross section was measured at η=\eta=3.3, 3.8 and 4.0 and was found to be consistent with next-to-leading order perturbative QCD calculations. The analyzing power was found to be zero at negative xFx_F and at positive xFx_F up to ~0.3, then increased with increasing xFx_F. This behavior can be described by phenomenological models including the Sivers effect, the Collins effect or higher twist contributions in initial and final states. Results for the analyzing power at η=\eta=3.7 and 4.0 from all data acquired at s=200\sqrt{s}=200 GeV and the status of the analysis of the s=410\sqrt{s}=410 GeV data will be presented. Future upgrade plans and status will also be discussed.

Keywords

Cite

@article{arxiv.hep-ex/0512013,
  title  = {Spin effects in large rapidity pi0 production at STAR},
  author = {D. A. Morozov},
  journal= {arXiv preprint arXiv:hep-ex/0512013},
  year   = {2019}
}

Comments

6 pages, 4 pictures, to be published in the proceedings of XI Workshop on High Energy Spin Physics, Dubna, Russia, September 27 - October 1, 2005

R2 v1 2026-07-22T13:06:10.716Z