Double spin asymmetries ANNANN and ASSASS at s=200 GeV in polarized proton–proton elastic scattering at RHIC

We present the first measurements of the double spin asymmetries A NN and A SS at √s = 200 GeV, obtained by the PP2PP experiment using polarized proton beams at the Relativistic Heavy Ion Collider (RHIC). The data were collected in the four momentum transfer t range 0.01 < |t| ≤ 0.03 (GeV/c) 2 . The measured asymmetries, which are consistent with zero, allow us to estimate upper limits on the double helicity-flip amplitudes Φ 2 and Φ 4 at small |t| as well as on the difference Δσ T between the total cross sections for transversely polarized protons with antiparallel or parallel spin orientations.