2026-09-20T17:12:40Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/132456 2026-02-20 col_2142_5131 col_2142_8859 com_2142_5130 com_2142_8858 com_2142_234

application/pdf en text Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2026-02-19 without embargo terms The student, Gregory Mattson, accepted the attached license on 2025-08-21 at 16:53. The student, Gregory Mattson, submitted this Dissertation for approval on 2025-08-21 at 17:02. This Dissertation was approved for publication on 2025-08-27 at 15:54. DSpace SAF Submission Ingestion Package generated from Vireo submission #22774 on 2026-02-19 at 18:24:11 Measurement of transverse single-spin asymmetries in π0 and η Meson production in √s = 200 GEV p↑ + p collisions with sPHENIX Mattson, Gregory 2025-08-27 Riedl, Caroline Sickles, Anne Grosse Perdekamp, Matthias Noronha, Jorge Eckstein, James nucleon structure TSSA transverse single-spin asymmetry sPHENIX eng The sPHENIX experiment is a next-generation collider detector at the Relativistic Heavy Ion Collider (RHIC) designed for rare jet and heavy-flavor probes of Au + Au, p + Au, and polarized p + p collisions. The experiment includes a large acceptance, granular electromagnetic calorimeter and very high-rate data acquisition plus trigger system. In RHIC Run-24, sPHENIX sampled 107 pb−1 of collision data with transversely polarized protons at √s = 200 GeV using an efficient high-pT photon trigger. This dissertation describes the extraction of transverse single-spin asymmetries in inclusive production of π0 and η mesons decaying into two photons. Such observables are sensitive to multi-parton correlations in the proton, which are related to transverse-momentum dependent (TMD) effects. The new sPHENIX data set allows for significant extension of the kinematic range covered by previous RHIC mid-rapidity measurements. The results are corrected for background contributions and three different sources of systematic uncertainties are considered: the calculation method, the method of background subtraction, and contributions from possible false asymmetries due to instrumental effects. The results are presented and compared to existing measurements from the PHENIX experiment. 2025-12 Thesis https://hdl.handle.net/2142/132456 Copyright 2025 Gregory Mattson Physics Physics University of Illinois Urbana-Champaign Ph.D. Dissertation