1 Communication JINR E2-97-78 Structure of spin-dependent scattering amplitude and spin eff.pdf

Communication JINR E2-97-78 1 Structure of spin-dependent scattering amplitude and spin effects at small angles at RHIC energies N. Akchurin Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, U.S.A. S. V. Goloskokov, O. V. Selyugin BLTPh, Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia (September 24, 1997) Abstract Spin-dependent pomeron effects are analyzed for elastic pp scattering and calculations for spin-dependent differential cross sections, analyzing power and double-spin correlation parameters are carried out for the energy range of the Relativistic Heavy Ion Collider (RHIC) at BNL. In this energy range, 50 ≤ √ s ≤ 500 GeV, the structure of pomeron-proton coupling can be measured at RHIC with colliding polarized proton beams. Typeset using REVTEX 2 I. INTRODUCTION The spin structure of the pomeron is still an unresolved question in the diffractive scatter- ing of polarized particles. There have been many observations of spin effects at high energies and at fixed momentum transfers [1,2]; several attempts to extract the spin-flip amplitude from the experimental data show that the ratio of spin-flip to spin-nonflip amplitudes can be non-negligible and may be independent of energy [3,4]. In all of these cases, the pomeron exchange is expected to contribute the observed spin effects at some level. The large ra- pidity events that are observed at CERN [5] and DESY [6], and all diffractive and elastic high energy reactions are predominated by pomeron exchange, thus making the pomeron a popular field of study. Extensive polarized physics programs are proposed at HERA, RHIC and LHC (see e.g. [7–9]) in order to shed light on these and other spin effects in hadron reactions. It is generally believed, based on calculations of the simplest QCD diagrams, that the spin effects diminish as inverse power of center-of-mass energy, and that the pomeron exchange does not lead to appreciable spin effects in the diffraction re