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

We present the first measurements of the double spin asymmetries A N N and A S S 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 Δ σ T between the total cross sections for transversely polarized protons with antiparallel or parallel spin orientations.