Accesing the Gluon Polarization through the Double Longitudinal Spin Asymmetrie in Charged Pion Production at PHENIX

TL;DR

This paper reports on the measurement of double longitudinal spin asymmetries in charged pion production at PHENIX, aiming to probe the gluon polarization within protons to improve understanding of proton spin structure.

Contribution

It provides new experimental data on charged pion asymmetries at mid-rapidity, contributing to the global analysis of gluon polarization in protons.

Findings

Measured asymmetries at pT of 5-10 GeV/c

Data constrains gluon polarization models

Supports previous indications of gluon contribution to proton spin

Abstract

With proton-proton collisions at PHENIX a variety of direct channels are used to probe the proton substructure. Of the many channels available at PHENIX, charged pion measurements are expected to have sensitivity of Delta g and thus help in the global analysis that will constrain it. We present a measurement of mid-rapidity charged pion production double longitudinal spin asymmetries (ALL) at the pT range of 5-10 GeV/c at collision energies of sqrt(s) = 200 GeV.