18-22 October 2021
Matsue, Shimane Prefecture, Japan
Asia/Tokyo timezone

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

22 Oct 2021, 07:54
Room 601 (Kunibiki Messe)

Room 601

Kunibiki Messe

Parallel Session Presentation Transverse momentum structure (TMD) Transverse Momentum Structure (TMD)


Christine Aidala (University of Michigan)


Recently published measurements from the PHENIX experiment at the Relativistic Heavy Ion Collider will be presented for the transverse single-spin asymmetries (TSSAs) of direct photons, neutral pions, and eta mesons produced at midrapidity in 200 GeV proton-proton collisions. As hadrons, neutral pions and eta mesons are sensitive to nonperturbative spin-momentum correlations both within the proton and in the process of hadronization; at midrapidity they probe the dynamics of gluons along with a mix of quark flavors. The direct photon TSSA measurement instead isolates initial-state spin-momentum correlations within the proton and at midrapidity provides a clean probe of the gluon dynamics in transversely polarized protons. All three of these results will help to constrain the collinear twist-3 trigluon correlation function. The direct photon result is the first-ever measurement of this observable from a hadron collider, and all three of the measurements represent the final, definitive results for these observables from the PHENIX experiment, which completed data taking with polarized beams in 2015.

Primary author

Christine Aidala (University of Michigan)

Presentation Materials