Description
We investigate the single spin asymmetry, $A_N(t)$, arising from Coulomb-nuclear interference (CNI) in small-angle elastic scattering. Previous theoretical predictions failed to explain the nontrivial $t$-dependence of $A_N$ in elastic proton-gold scattering, measured recently at RHIC.
We found that the absorptive corrections make the Coulomb amplitude of $pA$ elastic scattering cause significantly different from $eA$ scattering, leading
dramatic effects in $t$-dependence. Trying to be more precise, we also included in the elastic proton-nucleus amplitude the corrections, related to Gribov inelastic shadowing and $NN$ correlations.
Moreover, we demonstrate importance of the absorptive corrections also for the analysis of data on polarized $pp$ elastic scattering, which previously revealed a zero spin-flip part of the Pomeron. The absorption corrected analyses leads to an essentially non-zero hadronic spin-flip.
This can be tested in the forthcoming measurements by the STAR experiment at 510 GeV.
Finally, we investigate the contribution to $A_N$ from odderon-Pomeron interference.
