Measurement of charged pion double spin asymmetries at midrapidity in longitudinally polarized $p$$+$$p$ collisions at $\sqrt{s}=510$ GeV

Abstract

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the longitudinal double spin asymmetries, $A_{LL}$, for charged pions at midrapidity ($|\eta |<0.35$) in longitudinally polarized $p$$+$$p$ collisions at $\sqrt{s}=510$ GeV. These measurements are sensitive to the gluon spin contribution to the total spin of the proton in the parton momentum fraction $x$ range between 0.04 and 0.09. One can infer the sign of the gluon polarization from the ordering of pion asymmetries with charge alone. The asymmetries are found to be consistent with global quantum-chromodynamics fits of deep-inelastic scattering and data at $\sqrt{s}=200$ GeV, which show a nonzero positive contribution of gluon spin to the proton spin.

arXiv comment360 authors, 8 pages, 6 figures, 1 table, 2013 data. v2 is version accepted for publication in Physical Review D. 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 (12)

• PYTHIA 6.4 Physics and Manual
• PYTHIA 6.2 Physics and Manual
• A first unbiased global determination of polarized PDFs and their uncertainties
• Evidence for polarization of gluons in the proton
• Parton-to-Pion Fragmentation Reloaded
• Precision Measurement of the Longitudinal Double-spin Asymmetry for Inclusive Jet Production in Polarized Proton Collisions at $\sqrt{s}=200$ GeV
• Inclusive double-helicity asymmetries in neutral pion and eta meson production in $\vec{p}+\vec{p}$ collisions at $\sqrt{s}=200$ GeV
• Longitudinal double-spin asymmetry for inclusive jet and dijet production in $pp$ collisions at $\sqrt{s}=510$ GeV
• Inclusive cross section and double-helicity asymmetry for ${\pi }^0$ production at midrapidity in $p$$+$$p$ collisions at $\sqrt{s}=510$ GeV
• Measurement of the cross section and longitudinal double-spin asymmetry for di-jet production in polarized $pp$ collisions at $\sqrt{s}$ = 200 GeV
• Longitudinal Double-Spin Asymmetries for Dijet Production at Intermediate Pseudorapidity in Polarized $pp$ Collisions at $\sqrt{s}$ = 200 GeV
• Longitudinal Double-Spin Asymmetries for ${\pi }^0$s in the Forward Direction for 510 GeV Polarized $pp$ Collisions

Cited by in corpus (6)

• Conceptual design of the Spin Physics Detector
• Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab
• Accessing gluon polarization with high-$P_T$ hadrons in SIDIS
• Reflections on Chiral Symmetry within QCD
• Precision measurement of the longitudinal double-spin asymmetry for dijet production at intermediate pseudorapidity in polarized $pp$ collisions at $\sqrt{s}$ = 200 GeV
• Probing nucleon spin structure in deep-inelastic scattering, proton-proton collisions and Drell-Yan processes