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THE SPIN STRUCTURE OF THE NUCLEON.

Description: For many years now, spin has played a very prominent role in QCD. The field of QCD spin physics has been carried by the hugely successful experimental program of polarized deeply-inelastic lepton-nucleon scattering (DIS), and by a simultaneous tremendous progress in theory. A new milestone has now been reached with the advent of RHIC, the world's first polarized proton-proton collider. RHIC is poised to help answer many of the important question pertaining to the spin structure of the nucleon. Recently, it has also been proposed to study spin phenomena in transversely polarized {bar p}p collisions at the planned GSI-FAIR facility. This talk describes some of the opportunities provided by RHIC and the proposed GSI experiments.
Date: May 23, 2005
Creator: VOGELSANG, W.
Partner: UNT Libraries Government Documents Department

QCD Corrections in Transversely Polarized Scattering

Description: We discuss two recent calculations of higher-order QeD corrections to scattering of transversely polarized hadrons. A basic concept underlying much of the theoretical description of high-energy hadronic scattering is the factorization theorem, which states that large momentum-transfer reactions may be factorized into long-distance pieces that contain information on the structure of the nucleon in terms of its parton densities, and parts that are short-distance and describe the hard interactions of the partons. Two crucial points are that on the one hand the long-distance contributions are universal, i.e., they are the same in any inelastic reaction under consideration, and that on the other hand the short-distance pieces depend only on the large scales related to the large momentum transfer in the overall reaction and, therefore, may be evaluated using QCD perturbation theory. The lowest order for the latter can generally only serve to give a rough description of the reaction under study. It merely captures the main features, but does not usually provide a quantitative understanding. The first-order ('next-to-leading order' (NLO)) corrections are generally indispensable in order to arrive at a firmer theoretical prediction for hadronic cross sections, and in some cases even an all-order resummation of large perturbative corrections is needed. In the present paper we win discuss two calculations [1, 2] of higher-order QeD corrections to transversely polarized scattering.
Date: October 6, 2008
Creator: Vogelsang,W.
Partner: UNT Libraries Government Documents Department

Preliminary assessment of corrosion product transport in fusion reactors

Description: Corrosion which is tolerable from the standpoint of system mechanical integrity may cause substantial problems if the corrosion product is released and deposited at locations where it interferes with heat transfer or coolant flow. Furthermore, neutrons from the fusion reaction activate the corrosion product, causing radiation fields in maintenance areas near piping and components where the activated material deposits. Preliminary estimates suggest that formidable problems may occur in a lithium-cooled stainless steel primary circuit due to corrosion product deposition. If the estimated order of magnitude is confirmed in future studies, new concepts in corrosion control or corrosion product removal would need to be developed for lithium-cooled stainless steel CTR systems. Other fusion reactor system concepts and materials appear to offer alternatives which tend to minimize corrosion product transport. (auth)
Date: November 1, 1973
Creator: Johnson, A.B. Jr. & Vogelsang, W.F.
Partner: UNT Libraries Government Documents Department

SOME NEWS ON SPIN PHYSICS.

Description: For many years now, spin physics has played a very prominent role in QCD. The field has been carried by the hugely successful experimental program of polarized deeply-inelastic lepton-nucleon scattering (DIS), and by a simultaneous tremendous progress in theory. This talk summarizes some of the interesting new developments in spin physics in the past roughly two years. As we will see, there have yet again been exciting new data from polarized lepton-nucleon scattering, but also from the world's first polarized pp collider, RHIC. There have been very significant advances in theory as well. It will not be possible to cover all developments. The author will select those topics that may be of particular interest to the attendees of a conference in the ''DIS'' series. The author briefly reviews some of the recent developments in QCD spin physics.
Date: September 29, 2003
Creator: VOGELSANG,W.
Partner: UNT Libraries Government Documents Department

QCD SPIN PHYSICS IN HADRONIC INTERACTIONS.

Description: We discuss spin phenomena in high-energy hadronic scattering, with a particular emphasis on the spin physics program now underway at the first polarized proton-proton collider, RHIC. Experiments at RHIC unravel the spin structure of the nucleon in new ways. Prime goals are to determine the contribution of gluon spins to the proton spin, to elucidate the flavor structure of quark and antiquark polarizations in the nucleon, and to help clarify the origin of transverse-spin phenomena in QCD. These lectures describe some aspects of this program and of the associated physics.
Date: June 19, 2007
Creator: VOGELSANG,W.
Partner: UNT Libraries Government Documents Department

PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP ENTITLED "GLOBAL ANALYSIS OF POLARIZED PARTON DESTRIBUTIONS IN THE RHIC ERA" (VOLUME 86).

Description: The determination of the polarized gluon distribution is a central goal of the RHIC spin program. Recent achievements in polarization and luminosity of the proton beams in RHIC, has enabled the RHIC experiments to acquire substantial amounts of high quality data with polarized proton beams at 200 and 62.4 GeV center of mass energy, allowing a first glimpse of the polarized gluon distribution at RHIC. Short test operation at 500 GeV center of mass energy has also been successful, indicating absence of any fundamental roadblocks for measurements of polarized quark and anti-quark distributions planned at that energy in a couple of years. With this background, it has now become high time to consider how all these data sets may be employed most effectively to determine the polarized parton distributions in the nucleon, in general, and the polarized gluon distribution, in particular. A global analysis of the polarized DIS data from the past and present fixed target experiments jointly with the present and anticipated RHIC Spin data is needed.
Date: October 8, 2007
Creator: DESHPANDE,A. & VOGELSANG, W.
Partner: UNT Libraries Government Documents Department

EXPLORING THE POLARIZATION OF GLUONS IN THE NUCLEON.

Description: We give an overview of the current status of investigations of the polarization of gluons in the nucleon. We describe some of the physics of the spin-dependent gluon parton distribution and its phenomenology in high-energy polarized hadronic scattering. We also review the recent experimental results.
Date: October 22, 2007
Creator: STRATMANN,M. & VOGELSANG,W.
Partner: UNT Libraries Government Documents Department

QCD Spin Physics: Theoretical Overview

Description: We give an overview of some of the current activities and results in QCD spin physics. We focus on the helicity structure of the nucleon, where we highlight the results of a recent first global analysis of the helicity parton distributions, and on single-transverse spin asymmetries.
Date: November 9, 2008
Creator: Vogelsang,W.
Partner: UNT Libraries Government Documents Department

THRESHOLD RESUMMATION EFFECTS IN THE POLARIZED DRELL-YAN MECHANISM.

Description: We present theoretical predictions for the cross sections and spin asymmetries in dilepton pair production in transversely polarized pp and {bar p}p collisions. We use the available fixed-order corrections as well as the all-order resummation of threshold logarithms for the pair mass and rapidity distributions. Numerical results for pp collisions at {radical}s = 10 GeV at J-PARC and for {bar p}p collisions at {radical}s = 14.5 GeV at GSI-PAX are given.
Date: October 2, 2006
Creator: YOKOYA, H. & VOGELSANG, W.
Partner: UNT Libraries Government Documents Department

Prompt Photon Production in Polarized Hadron Collisions.

Description: We consider spin asymmetries for prompt photon production in collisions of longitudinally polarized hadrons. This reaction will be a key tool at the BNL-RHIC {rvec p}{rvec p} collider for determining the gluon spin density in a polarized proton. We study the effects of QCD corrections, such as all-order soft-gluon ''threshold'' resummations.
Date: April 25, 2000
Creator: Vogelsang, W.
Partner: UNT Libraries Government Documents Department

COMPARING EXTRACTIONS OF SIVERS FUNCTIONS.

Description: A comparison is given of the various recently published extractions of the Sivers functions from the HERMES and COMPASS data on single-transverse spin asymmetries in semi-inclusive deeply inelastic scattering.
Date: September 7, 2005
Creator: VOGELSANG, W.
Partner: UNT Libraries Government Documents Department

THE RESUMMED HIGGS BOSON TRANSVERSE MOMENTUM DISTRIBUTION AT THE LHC.

Description: We apply QCD resummation techniques to study the transverse momentum distribution of Higgs bosons produced via gluon-gluon fusion at the LHC. In particular we focus on the joint resummation formalism which resume both threshold and transverse momentum corrections simultaneously. A comparison of results obtained in the joint and the standard recoil resummation frameworks is presented.
Date: December 8, 2003
Creator: KULESZA,A. STERMAN,G. VOGELSANG,W.
Partner: UNT Libraries Government Documents Department

PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP: THEORY STUDIES FOR POLARIZED PP SCATTERING (VOLUME 53)

Description: In the past two runs of RHIC, the first measurements with polarized proton beams have been performed. For many years to come, the RHIC spin program will offer exciting physics, exploring QCD and the nucleon in new ways. The aim of this small workshop was to attract several spin theorists to the center for about two weeks, in order to collaborate with both experimentalists and theorists at RBRC, and to initiate and/or complete studies of relevance to RHIC spin. A major focus of polarized-pp measurements at RHIC is on measuring the spin-dependent gluon density, {Delta}g. A channel for accessing {Delta}g is high-p{sub T} pion production. The unpolarized cross section for this reaction has been measured by PHENIX and was found in good agreement with a perturbative-QCD based (NLO) calculation. It was a remarkable and exciting coincidence that PHENIX presented also the first results for the spin asymmetry for {rvec p}{rvec p} {yields} {pi}{sup 0}X during this workshop. This sparked a lot of additional activity and discussion. First steps toward the interpretation of the data were taken. Marco Stratmann and Barbara Jager (Regensburg University) presented recent work on the NLO calculation of the polarized cross section and the spin asymmetry, setting the stage for future full analysis of the data in terms of {Delta}g. Applications to {rvec e}{rvec p} scattering, very relevant to eRHIC, were also worked out and published during this workshop. Stratmann also discussed the procedure of NLO calculations for the case of transverse polarization in pp scattering.
Date: September 15, 2003
Creator: KRETZER,S. VOGELSANG,W.
Partner: UNT Libraries Government Documents Department