Double helicity asymmetry in inclusive midrapidity π0 production for polarized p + p collisions at √s = 200 GeV

Abstract

A technique for determining the polarized gluon distribution using polarized protons, was presented. The transverse beam polarization was measured in Relativistic Heavy Ion Collider (RHIC) independently in each beam using proton-carbon elastic scattering in the Coulomb nuclear interference region. The results of the double spin helicity asymmetries for π0 production began to probe the proton spin structure in the perturbative quantum chromodynamic (QCD) regime with a sensitivity comparable to the polarized inclusive deep inelastic scattering data. The observed symmetry was small and was compared to a next-to-leading-order perturbative (NLO pQCD) calculation with a range of polarized gluon distributions.