Online Reconstruction on GPUs for J/ψ TSSA Study at SpinQuest*

The E1039/SpinQuest experiment is a transversely polarized fixed target experiment at Fermi National Accelerator Laboratory aiming to explore the sea quark and gluon Sivers functions via the measurement of the transverse single-spin asymmetry (TSSA) for a number of physics processes including J/ψ, ψ' and Drell-Yan production. The experiment employs a 120-GeV extracted proton beam colliding with transversely-polarized NH3 and ND3 cryogenic targets and its spectrometer is optimized to detect the oppositely-charged muon pair output of these processes. In pursuit of these asymmetry measurements, we are developing an advanced graphics processing unit (GPU) based multi-threaded framework that allows for efficient parallelization of the online data processing flow and track reconstruction along with diagnostics and visualization tools. In this talk, I will report performance metrics and the status of optimization of the offline track reconstruction software at SpinQuest on GPUs and discuss how we are implementing and reaching successful real-time data visualization and monitoring in preparation for SpinQuest's first production run in 2022. Moreover, I will present results estimating the anticipated precision of a TSSA measurement via the J/ψ process from the first SpinQuest production data as well as its associated efficiency studies.