Improving constraints on gluon spin-momentum correlations in transversely polarized protons via midrapidity open-heavy-flavor electrons in $p^{\uparrow}+p$ collisions at $\sqrt{s}=200$ GeV

TL;DR

This study measures transverse single-spin asymmetries of electrons from heavy-flavor decays in polarized proton collisions to better understand gluon spin-momentum correlations and constrain related gluon distribution models.

Contribution

It provides new experimental constraints on gluon correlators in transversely polarized protons using midrapidity heavy-flavor electron measurements at RHIC.

Findings

Constraints on gluon correlators are extracted for two models.

Charge-separated measurements improve sensitivity to gluon dynamics.

Results enhance understanding of gluon contributions to proton spin.

Abstract

Polarized proton-proton collisions provide leading-order access to gluons, presenting an opportunity to constrain gluon spin-momentum correlations within transversely polarized protons and enhance our understanding of the three-dimensional structure of the proton. Midrapidity open-heavy-flavor production at $\sqrt{s}=200$ GeV is dominated by gluon-gluon fusion, providing heightened sensitivity to gluon dynamics relative to other production channels. Transverse single-spin asymmetries of positrons and electrons from heavy-flavor hadron decays are measured at midrapidity using the PHENIX detector at the Relativistic Heavy Ion Collider. These charge-separated measurements are sensitive to gluon correlators that can in principle be related to gluon orbital angular momentum via model calculations. Explicit constraints on gluon correlators are extracted for two separate models, one of which had not been constrained previously.