Speaker
Description
The transverse single-spin asymmetry, $A_N$, in isolated-photon production in transversely polarized $p^{\uparrow}+p$ collisions is of particular interest for studies of polarized proton structure. Isolated photons provide a clean probe of initial-state spin-dependent parton dynamics, as they are largely insensitive to final-state interactions and are dominated by quark–gluon scattering at RHIC energies. This measurement can provide constraints on quark–gluon and tri-gluon correlation functions within the proton while the latter remains only weakly constrained by existing data. sPHENIX, a new experiment at RHIC, provides a unique opportunity for a clean measurement of isolated-photon $A_N$, with full electromagnetic and hadronic calorimeter coverage at midrapidity. In this talk, we will present the status of the isolated-photon $A_N$ analysis using $p^{\uparrow}+p$ collision data collected in 2024 at $\sqrt{s}=200$ GeV, corresponding to an integrated luminosity of $107 \, \rm{pb}^{-1}$.