SPIN EFFECTS IN LARGE RAPIDITY NEUTRAL PION PRODUCTION AT STAR.
Conference
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OSTI ID:876641
- FOR THE STAR COLLABORATION
Measurements by the STAR collaboration of neutral pion production at large Feynman x (x{sub F}) in the first polarized proton collisions at {radical}s = 200 GeV were reported previously. During the following two runs additional statistics were acquired with an improved forward calorimeter for the {pi}{sup 0} cross-section and analyzing power measurements. First data from pp collisions at {radical}s = 410 GeV were taken during the RHIC run that ended in June, 2005. The cross section was measured at {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 23 and at positive x{sub F} up to 0.3, then increased with increasing x{sub 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 {eta} = 3.7 and 4.0 from all data acquired at {radical}s = 200 GeV and the status of the analysis of the {radical}s = 410 GeV data will be presented. Future upgrade plans and status will also be discussed.
- Research Organization:
- BROOKHAVEN NATIONAL LABORATORY
- Sponsoring Organization:
- DOE/SC
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 876641
- Report Number(s):
- BNL--75443-2006-CP; KB-02-01
- Country of Publication:
- United States
- Language:
- English
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