Proton-helium elastic scattering: a possible high-energy polarimeter at RHIC-BNL
Abstract We examine a suggestion to use p- 4 He elastic scattering, as an absolute polarimeter for high-energy polarized proton beams, by means of a Coulomb-Nuclear Interference effect for the single-spin asymmetry A N ( t ), around the diffractive minimum of the differential cross section |t|∼0.21 GeV 2 . Although this reaction has a fairly simple dynamical structure, our theoretical uncertainties and the present experimental inaccuracy of the differential cross section in this t region, allows one to generate dramatic effects for A N ( t ), which will be discussed.
Spin-flip component of the pomeron
Abstract The spin-flip pomeron amplitude is estimated in the Born approximation of QCD using the nonrelativistic quark model for the nucleon wave function. A nonzero result is possible if the nucleon contains a dynamically enhanced component with a compact diquark. The proposed model-independent way of the pomeron spin-flip measurement in the Coulomb-nuclear interference region is now in progress in the experiment E-704 at the Fermilab TEVATRON.
Comment on diquark fragmentation
We discuss diquark fragmentation and suggest that a spectator $\mathrm{uu}$ system in deep-inelastic lepton-nucleon scattering has a larger breakup probability than a $\mathrm{ud}$ system. The reason for this is argued to be that half of the leftover $\mathrm{ud}$ systems are in bound ${(\mathrm{ud})}_{0}$ diquark configurations, while no such bound $\mathrm{uu}$ diquarks exist.