Precision small scattering angle measurements of proton-proton and proton-nucleus analyzing powers at the RHIC hydrogen jet polarimeter

At RHIC, the hydrogen jet target polarimeter (HJET) is used to measure proton beam polarization with accuracy $\sigma_P^\text{syst}/P\lesssim0.5\%$ by counting low energy (1--10 MeV) recoil protons in left-right symmetric detectors. The HJET performance also allowed us to precisely measure $pp$ and $p$A (where A is any ion stored at RHIC) analyzing powers in the CNI region. The results of the measurements are discussed.