Cross Section and Double Helicity Asymmetry in Charged Hadron Production in p+p Collisions at sqrt(s)=62.4 GeV at PHENIX

TL;DR

This paper reports measurements of the cross section and double-helicity asymmetry for charged hadron production in proton-proton collisions at 62.4 GeV, testing QCD predictions and probing gluon spin contributions.

Contribution

It provides new experimental data at intermediate energy, extending the understanding of gluon polarization and testing perturbative QCD calculations in this energy regime.

Findings

Cross section agrees with NLO and NLL pQCD calculations.

Double-helicity asymmetry constrains gluon polarization at moderate x.

Results extend gluon spin measurements to higher momentum fractions.

Abstract

The cross section and double-helicity asymmetry for production of non-identified positive and negative charged hadrons at midrapidity in p+p collisions at sqrt(s) = 62.4 GeV have been measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) for a transverse momentum range of 0.5-4.5 GeV/c. The cross section measurements are compared to next-to-leading order and next-to-leading log perturbative QCD calculations, providing information on the applicability of these calculation techniques in the measured kinematic range. The double-helicity asymmetry measurement at this moderate energy provides sensitivity to Delta G, the gluon spin contribution to the spin of the proton, up to modestly larger values of the gluon momentum fraction than previous RHIC measurements at 200 GeV.