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.
THE QCD ANALYSIS OF THE COMBINED SET FOR THE F 3 STRUCTURE FUNCTION DATA BASED ON THE ANALYTIC APPROACH
We apply analytic perturbation theory (APT) to the QCD analysis of the xF3(x, Q2) structure function considering a combined set of deep inelastic scattering data presented by several collaborations, and extract values of the scale parameter ΛQCD, the parameters of the form of the xF3 structure function, and the x-shape of the higher twist (HT) contribution. We study the difference between the results obtained within the standard perturbative and analytic approaches in comparison with the experimental errors and state that the greatest difference occurs for large x.
A diquark scattering model for highpT proton production inpp collisions at the ISR
The relative yield of high transverse momentum protons measured inpp interctions at the CERN ISR is calculated in the framework of simple parton models. Whereas models based exclusively on quark and gluon scattering fail to describe the data, the hypothesis of diquark scattering provides a quantitative understanding of the measured dependences on transverse momentum, polar angle, and centre-of-mass energy. Different assumptions on diquark structure functions are tested.