In the JPAC model, the rho SDMEs in the helicity frame at 8.5 GeV beam energy are mainly sensitive to the f2 and Pomeron exchanges, and hence to the corresponding vertex couplings. The f2 contributions dominate the deviations from SCHC,while the Pomeron dilutes them. Since the ratio of Pomeron /f2 increases with beam energy , the deviations from SCHC become quite small by 25 GeV. The 3 unpolarized SDMEs have similar sensitivities to the 6 polarized SDMEs, so might provide useful parameter constraints over the full beam energy range of GlueX . It’s not clear to me what’s going on with the Natural versions of the SDMEs; while the unnatural versions are indeed relatively small, the natural versions don’t show the purity I was naively expecting at 8.5 GeV.
