Overview Of Transverse Spin Physics In The Phenix Experiment

This book is devoted to the theory and phenomenology of transverse-spin effects in high-energy hadronic physics. Contrary to common past belief, it is now rather clear that such effects are far from irrelevant. A decade or so of intense theoretical work has shed much light on the subject and brought to surface an entire class of new phenomena, which now await thorough experimental investigation. Over the next few years a number of experiments world-wide (at BNL, CERN, DESY and JLAB) will run with transversely polarised beams and targets, providing data that will enrich our knowledge of the transverse-spin structure of hadrons. It is therefore timely to assess the state of the art, and this is the principal aim of the volume.An outline of the book is as follows. After a few introductory remarks (Chapter 1), attention is directed in Chapter 2 to transversely polarised deeply-inelastic scattering (DIS), which probes the transverse spin structure function g2. This existing data are reviewed and discussed (for completeness, a brief presentation of longitudinally polarised DIS is also provided). In Chapter 3 the transverse-spin structure of the proton is illustrated in detail, with emphasis on the transversity distribution and the twist-three parton distribution contributing to g2. Model calculations of these quantities are also presented. In Chapter 4, the QCD evolution of transversity is studied at leading and next-to-leading order. Chapter 5 illustrates the g2 structure function and its related sum rules within the framework of perturbative QCD. The last three chapters are devoted to the phenomenology of transversity, in the context of Drell-Yan processes (Chapter 6), inclusive leptoproduction (Chapter 7) and inclusive hadroproduction (Chapter 8). The interpretation of some recent single-spin asymmetry data is discussed and the prospects for future measurements are reviewed.

The PHENIX experiment at RHIC has extended its scope to cover spin physics using polarized proton beams. The major goals of the spin physics at RHIC are elucidation of the spin structure of the nucleon and precision tests of the symmetries. Sensitivities of the spin physics measurements with the PHENIX detector system are reviewed.

In recent years, there has been considerable growth in research activities related to spin phenomena in high energy physics and their theoretical interpretations. It has become clear that the spin enigma is not to be considered separately but that it is strongly related to the quark-gluon structure of hadrons and their interaction dynamics.Research on spin phenomena has now attracted a significant following of experimental and theoretical physicists who meet regularly at symposiums on the topic.This book serves as an introduction to the spin puzzles at high energies. Its main focus is on spin effects in hadronic processes and the spin structure of nucleons.The volume will be very useful for graduate students and for those working in the field of polarization physics or interested in the various aspects of strong interaction dynamics. The only book on spin phenomena in high energy physics, it fulfils the great need for an introductory volume in this area of growing interest.

The PHENIX experiment took data with transversely polarized proton beams in 2001-2002 and measured the transverse single spin asymmetries in inclusive neutral pion and non-identified charge hadrons at midrapidity and (square root) s = 200 GeV. The data near X{sub F} (almost equal to) 0 cover a transverse momentum range from 0.5 to 5.0 GeV/c. The observed asymmetries are consistent with zero with good statistical accuracy. This paper presents the current work in light of earlier measurements at lower energies in this kinematic region and the future plans of the PHENIX detector.

The volume presents an up-to-date survey of spin physics at the very high energies of present and future colliders. Topics discussed include the theory of high-energy spin physics, deep-inelastic scattering, polarization experiments at colliders, the production of high-energy polarized electron and proton beams, the construction of intense polarized sources and high-energy polarimeters. It will represent a significant reference in the field and an informative text for non-specialists as well, with rather complete keynote overview reports by some physicists who have contributed most to the subject. In addition, it will document the character of frontier research symposium of the Conference, with specialized reports of leading experts in the various items of the field.

Getting down to the bottom line is what this proceedings digest is all about, as any physicist will tell you: spin is the fundamental concept in physics. The applications are pretty universal due to the fact that, using spin-related phenomena, physicists are trying to reveal the fundamental principles of nature – and things don’t come much more bottom-line than that. This volume is the proceedings of the 17th International Spin Physics Symposium which is a forum to discuss spin physics and related topics.

Transverse-spin physics has been very active and rapidly developing in the last few years. In this talk, I will briefly summarize recent theoretical developments, focusing on the associated QCD dynamics in transverse spin physics.