# Transverse Single-Spin Asymmetries of Midrapidity Direct Photons and Neutral Mesons at PHENIX

### Submission summary

 As Contributors: Nicole Lewis Arxiv Link: https://arxiv.org/abs/2107.10079v2 (pdf) Date accepted: 2022-05-06 Date submitted: 2022-03-18 16:10 Submitted by: Lewis, Nicole Submitted to: SciPost Physics Proceedings Proceedings issue: DIS2021 Academic field: Physics Specialties: High-Energy Physics - Experiment Nuclear Physics - Experiment Approach: Experimental

### Abstract

Results are presented for the transverse single-spin asymmetries of direct photons, neutral pions, and eta mesons for $|\eta|<0.35$ from $p^\uparrow + p$ collisions with $\sqrt{s} = 200$ GeV at PHENIX. As hadrons, $\pi^0$ and $\eta$ mesons are sensitive to both initial- and final-state effects and at midrapidity probe the dynamics of gluons along with a mix of quark flavors. Because direct photon production does not include hadronization, the direct photon TSSA is only sensitive to initial-state effects and at midrapidity provides a clean probe of the gluon dynamics in transversely polarized protons. All three of these results will help constrain the collinear twist-3 trigluon correlation function as well as the gluon Sivers function, improving our knowledge of spin-dependent gluon dynamics in QCD.

Published as SciPost Phys. Proc. 8, 009 (2022)

### Submission & Refereeing History

#### Published as SciPost Phys. Proc. 8, 009 (2022)

Resubmission 2107.10079v2 on 18 March 2022
Submission 2107.10079v1 on 22 July 2021