Effect of polarized gluon distribution on spin asymmetries for neutral   and charged pion production
  A longitudinal double spin asymmetry for \pi^0 production has been measured by the PHENIX collaboration. The asymmetry is sensitive to the polarized gluon distribution and is indicated to be positive by theoretical predictions. We study a correlation between behavior of the asymmetry and polarized gluon distribution in neutral and charged pion production at RHIC. 
Masanori Hirai and Kazutaka Sudoh