Energy dependence of CNI analyzing power for proton-carbon scattering

Abstract

We use a simple Regge model to determine the energy dependence of the analyzing power for pC scattering in the CNI region. We take the model of Cudell et al which determines the Regge couplings and intercepts for the I=0, non-flip Regge exchanges (Pomeron, f1 and ω) and extend it to the spin-flip amplitudes by allowing each of these exchanges to have independent spin-flip factors tau_P, tau_f and tau_ω. Using this we show that by making measurments at two separate energies, with polarization known at one energy, one can fix the ratios of the analyzing power at any energy. By making an additional assumption that is reasonable, but not necessarily true, namely tau_ω=tau_f, we show that one can predict the energy dependence of the analyzing power {using the existing E950 data}. We present the corresponding predictions for beam energies of 100 GeV and 250 GeV protons on a fixed carbon target based on a fit to the Spin 2000 data. Finally, we discuss the relation of these results to the pp CNI analyzing power.