CNI polarimetry with [sup 3]He

Abstract

By making use of previous analysis of CNI for pp and pC scattering, the spin-flip factor for np scattering is determined as a function of energy and then used to calculate the p^He asymmetry ^iv(-5)' arising in p^He elastic scattering. It is found to be comparable to Ai</{s) ior pp scattering, but of the opposite sign. It seems that this method could be a practical for measuring the polarization oia^He beam.

Forward Helion Scattering and Neutron Polarization

“…The spin polarized neutrons available from a polarized helium-3 beam would be very suitable for the study of polarized down quarks in various QCD processes particularly relating to transversity [1], nucleon spin structure [2], multi Pomeron exchange [3], gluon distributions [4], and additional dimensions [5]. Measuring the analyzing power in small angle elastic scattering of hadrons with spin provides an opportunity for evaluating the level of polarisation of incident helium-3 nuclei (helions) [6] thereby providing an effective neutron polarimeter [7]. Such a method relies upon an understanding of high energy spin dependence in diffractive processes [8].…”

“…Here, the interference of elastic hadronic and electromagnetic interactions in a suitable peripheral region enhances the size of the transverse spin asymmetry sufficiently to offer a tangible polarimeter for high energy helions. Polarimetry has been studied [7] in an approximation which emphasises the rôle of the neutron and the Glauber corrections that are required for a light nucleus such as helium-3.…”