Spin dependence in polarized elastic scattering in the CNI region

The interference of the electromagnetic spin-flip amplitude with a hadronic spin-nonflip amplitude in elastic scattering leads to significant spin dependencies at very low momentum transfer t. Recent results on A(N) and A(NN) in polarized proton-proton elastic scattering at very low t using a polarized atomic hydrogen gas jet target and the 100 GeV/c polarized proton beam are at RHIC are presented. Our A(N) pp data are well described with the electromagnetic spin-flip alone and do not support the presence of a large hadronic spin-flip amplitude. The double spin asymmetry A(NN) is found to be consistent with zero over the whole measured t range, indicating that double spin-flip amplitudes do not play a role in this kinematical region.