Double Helicity Asymmetry in Inclusive Mid-Rapidity neutral pion Production for Polarized p+p Collisions at sqrt(s)=200 GeV

Abstract

We present a measurement of the double longitudinal spin asymmetry in inclusive pi^0 production in polarized proton-proton collisions at sqrt(s)=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 26%. The measurements are the first of a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1-5 GeV/c at mid-rapidity, where next-to-leading order perturbative quantum chromodynamic (NLO pQCD) calculations describe the unpolarized cross section well. The observed asymmetry is small and is compared with a NLO pQCD calculation with a range of polarized gluon distributions.

arXiv comment326 authors, 6 pages text, RevTeX, 3 figures, 1 table. To be submitted to PRL. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.html

References in corpus (11)

• Models for the Polarized Parton Distributions of the Nucleon
• Measurements of the $Q^2$-Dependence of the Proton and Neutron Spin Structure Functions g1p and g1n
• Mid-Rapidity Neutral Pion Production in Proton-Proto Collisions at sqrt(s_NN) = 200 GeV
• QCD Analysis of Polarized Deep Inelastic Data and Parton Distributions
• The RHIC Zero Degree Calorimeter
• Next-to-leading order QCD corrections to high-p_T pion production in longitudinally polarized pp collisions
• Measurement of the Spin Asymmetry in the Photoproduction of Pairs of High-pT Hadrons at HERMES
• Determination of polarized parton distribution functions and their uncertainties
• Single-Inclusive Jet Production in Polarized pp Collisions at O(alpha_s^3)
• Measurement of Analyzing Power for Proton-Carbon Elastic Scattering in the Coulomb-Nuclear Interference Region with a 22-GeV/c Polarized Proton Beam
• QCD Hard Scattering and the Sign of the Spin Asymmetry A_LL^pi

Cited by in corpus (37)

• Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration
• A first unbiased global determination of polarized PDFs and their uncertainties
• Determination of fragmentation functions and their uncertainties
• Inclusive cross section and double helicity asymmetry for π^0 production in p+p collisions at sqrt(s)=200 GeV: Implications for the polarized gluon distribution in the proton
• The Spin Structure of the Proton
• Longitudinal double-spin asymmetry and cross section for inclusive jet production in polarized proton collisions at sqrt(s) = 200 GeV
• Deeply Virtual Compton Scattering off the neutron
• A Detailed Study of High-pT Neutral Pion Suppression and Azimuthal Anisotropy in Au+Au Collisions at \sqrt{s_{NN}} = 200 GeV
• Sea quark and gluon polarization in the nucleon at NLO accuracy
• Inclusive cross section and double helicity asymmetry for pi^0 production in p+p collisions at sqrt(s) = 62.4 GeV
• High transverse momentum eta meson production in p+p, d+Au and Au+Au collisions at sqrt(s_NN) = 200 GeV
• The gluon spin contribution to the proton spin from the double helicity asymmetry in inclusive pi^0 production in polarized p+p collisions at sqrt(s)=200 GeV
• Impact of CLAS and COMPASS data on Polarized Parton Densities and Higher Twist
• Physics of Gluon Helicity Contribution to Proton Spin
• Determination of polarized parton distribution functions with recent data on polarization asymmetries
• Leading-Order Determination of the Gluon Polarization from high-$p_T$ Hadron Electroproduction
• Gluon Helicity Delta G from a Universality Class of Operators on a Lattice
• Neutral pion cross section and spin asymmetries at intermediate pseudorapidity in polarized proton collisions at sqrt{s} = 200 GeV
• Double hadron leptoproduction in the nuclear medium
• Improved Measurement of Double Helicity Asymmetry in Inclusive Midrapidity pi^0 Production for Polarized p+p Collisions at sqrt(s)=200 GeV
• Longitudinally Polarized Photoproduction of Inclusive Hadrons at Fixed-Target Experiments
• Analysis of the double-spin asymmetry A_LT in inelastic nucleon-nucleon collisions
• Spin physics and TMD studies at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC)
• PHENIX Upgrade: Novel Stripixel Detector for Heavy Quark Detection and Proton Spin Structure Measurements at RHIC Energies
• Anti-Hyperon polarization in high energy pp collisions with polarized beams
• Exploring the polarization of gluons in the nucleon
• First Extraction of Transverse Momentum Dependent Helicity Distributions
• Probing gluon helicity with heavy flavor at the EIC
• Next-to-Leading Order QCD Corrections to Heavy Quark Correlations in Longitudinally Polarized Hadron-Hadron Collisions
• Constraints on gluon polarization in the nucleon at NLO accuracy
• Hard scattering and jets--from p-p collisions in the 1970's to Au+Au collisions at RHIC
• Effect of polarized gluon distribution on spin asymmetries for neutral and charged pion production
• Hadron-Pair Photoproduction in Longitudinally Polarized Lepton-Nucleon Collisions
• Direct Estimate of the Gluon Polarization in the Nucleon
• Measurement of the Transverse Single-Spin Asymmetry for Mid-rapidity Production of Neutral Pions in Polarized p+p Collisions at 200 GeV Center-of-Mass Energy
• Intrinsic parton motion soft mechanisms and the longitudinal spin asymmetry A_LL in high energy pp -> pi X
• Proton Structure and PHENIX Experiment