Single-spin asymmetry of inclusive γ production in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$p_ \uparrow p$$ \end{document} interactions at 200 GeV/c

From the data of Fermilab polarization experiment E704, the analyzing power ANγ of inclusively produced photons was extracted. It is small, of the order of 2–4%. The analyzing power of “leading” photons (the fastest in π0 → γγ decay) is a factor of 2 higher than ANγ assuming a definite model for xF dependence of ANγ. A Monte Carlo simulation is performed in order to see effects at higher statistics than in the E704 experiment. This simulation showed that the process of inclusive photons may be used as a basis for future polarimetry at polarized colliders. The example of one local photon polarimeter at RHIC is discussed.