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UNIQUE DESCRIPTION FOR SINGLE TRANSVERSE SPIN ASYMMETRIES IN DIS AND HADRONIC COLLISIONS.

Description: We derive a unique formula for the single-transverse-spin asymmetry in semi-inclusive hadron production in deep inelastic scattering, valid for all transverse momentum region. Based on this, we further study the integrated asymmetry weighted with transverse-momentum. They can be evaluated in terms of the twist-three quark-gluon correlation functions, which are responsible for the single spin asymmetry in single inclusive hadron production in hadronic collisions. By using the fitted twist-three functions from the hadronic collision data, we find a consistent description for SSAs in deep inelastic scattering. This demonstrates that we have a unique picture for SSAs in these two processes, and shall provide important guidelines for future studies.
Date: December 18, 2006
Creator: YUAN, F.
Partner: UNT Libraries Government Documents Department

Transverse momentum dependent quark distributions and polarized Drell-Yan processes

Description: We study the spin-dependent quark distributions at large transverse momentum. We derive their transverse momentum behaviors in the collinear factorization approach in this region. We further calculate the angular distribution of the Drell-Yan lepton pair production with polarized beams and present the results in terms of the collinear twist-three quark-gluon correlation functions. In the intermediate transverse momentum region, we find that the two pproaches: the collinear factorization and the transverse momentum dependent factorization approaches are consistent in the description of the lepton pair angular distributions.
Date: September 11, 2009
Creator: Zhou, J.; Yuan, F. & Liang, Z.-T.
Partner: UNT Libraries Government Documents Department

Semi-inclusive DIS:Factorization

Description: In this talk, we win present a QCD factorization theorem for the semi-inclusive deep-inelastic scattering with hadrons in the current fragmentation region detected at low transverse momentum.
Date: April 7, 2008
Creator: Yuan,F.
Partner: UNT Libraries Government Documents Department

Collins Mechanism Contributions to Single Spin Asymmetry

Description: We present recent developments on the single transverse spin physics, in particular, the Collins mechanism contributions in various hadronic reactions, such as semi-inclusive hadron production in DIS process, azimuthal distribution of hadron in high energy jet in pp collisions. We will demonstrate that the transverse momentum dependent and collinear factorization approaches are consistent with each other in the description of the Collins effects in the semi-inclusive hadron production in DIS process.
Date: May 25, 2009
Creator: Yuan,F.
Partner: UNT Libraries Government Documents Department

Collins Mechanism Contributions to Single Spin Asymmetry

Description: We present recent developments on the single transverse spin physics, in particular, the Collins mechanism contributions in various hadronic reactions, such as semi-inclusive hadron production in DIS process, azimuthal distribution of hadron in high energy jet in pp collisions. We will demonstrate that the transverse momentum dependent and collinear factorization approaches are consistent with each other in the description of the Collins effects in the semi-inclusive hadron production in DIS process.
Date: May 26, 2009
Creator: Yuan,F.
Partner: UNT Libraries Government Documents Department

Proceedings of RIKEN BNL Research Center Workshop: Brookhaven Summer Program on Nucleon Spin Physics

Description: Understanding the structure of the nucleon is of fundamental importance in sub-atomic physics. Already the experimental studies on the electro-magnetic form factors in the 1950s showed that the nucleon has a nontrivial internal structure, and the deep inelastic scattering experiments in the 1970s revealed the partonic substructure of the nucleon. Modern research focuses in particular on the spin and the gluonic structure of the nucleon. Experiments using deep inelastic scattering or polarized p-p collisions are carried out in the US at the CEBAF and RHIC facilities, respectively, and there are other experimental facilities around the world. More than twenty years ago, the European Muon Collaboration published their first experimental results on the proton spin structure as revealed in polarized deep inelastic lepton-nucleon scattering, and concluded that quarks contribute very little to the proton's spin. With additional experimental and theoretical investigations and progress in the following years, it is now established that, contrary to naive quark model expectations, quarks and anti-quarks carry only about 30% of the total spin of the proton. Twenty years later, the discovery from the polarized hadron collider at RHIC was equally surprising. For the phase space probed by existing RHIC experiments, gluons do not seem to contribute any to the proton's spin. To find out what carries the remaining part of proton's spin is a key focus in current hadronic physics and also a major driving force for the new generation of spin experiments at RHIC and Jefferson Lab and at a future Electron Ion Collider. It is therefore very important and timely to organize a series of annual spin physics meetings to summarize the status of proton spin physics, to focus the effort, and to layout the future perspectives. This summer program on 'Nucleon Spin Physics' held at Brookhaven National Laboratory (BNL) on July 14-27, ...
Date: August 2, 2011
Creator: Aschenauer, A.; Qiu, Jianwei; Vogelsang, W. & Yuan, F.
Partner: UNT Libraries Government Documents Department

PKU-RBRC Workshop on Transverse Spin

Description: Understanding the structure of the nucleon is a fundamental question in subatomic physics, and it has been under intensive investigation for the last several years. Modern research focuses in particular on the spin structure of the nucleon. Experimental and theoretical investigations worldwide over the last few decades have established that, contrary to nave quark model expectations, quarks carry only about 30% of the totd spin of the proton. The origin of the remaining spin is the key question in current hadronic physics and also the major driving forces for the current and future experiments, such as RHIC and CEBAF in US, JPARC in Japan, COMPASS at CERN in Europe, FAIR at GSI in Germany. Among these studies, the transverse-spin physics develops actively and rapidly in the last few years. Recent studies reveal that transverse-spin physics is closely related to many fundamental properties of the QCD dynamics such as the factorization, the non-trivial universality of the parton distribution and fragmentation functions. It was very timely to bring together the theorists and experimentalists in this field at this workshop to review and discuss the latest developments and future perspective in hadronic spin physics. This workshop was very success iu many aspects. First of all, it attracted almost every expert working in this field. We had more than eighty participants in total, among them 27 came from the US institutes, 13 from Europe, 3 from Korea, and 2 from Japan. The rest participants came from local institutes in China. Second, we arranged plenty physics presentations, and the program covers all recent progresses made in the last few years. In total, we had 47 physics presentations, and two round table discussions. The discussion sessions were especially very useful and very much appreciated by all participants. In addition, we also scheduled plenty time for discussion ...
Date: June 30, 2008
Creator: Avakian,H.; Bunce, G. & Yuan, F.
Partner: UNT Libraries Government Documents Department

Structure and transport properties of [001] tilt grain boundaries in YBa{sub 2}Cu{sub 3}O{sub x}

Description: We have studied the microstructure and transport properties of nominal [001] tilt grain boundaries in order to correlate microstructural features with transport properties. single grain boundaries were prepared by epitaxial growth of YBa{sub 2}Cu{sub 3}O{sub x} onto bi-crystal SrTiO{sub 3} substrates. Transport measurements were used to characterize the electrical behavior across the boundary while TEM was used to characterize the structure of the boundary. The transport measurements are consistent with grain boundary behavior, but detailed comparisons show anomalies which may be resolved by microstructural characterization. Microstructural characterization showed that these artificially induced grain boundaries are periodically decorated by impurity phases. In addition, the boundaries are not always straight, but instead frequently meander away from the path of the underlying boundary in the substrate, and the various facets produced by the meandering show varying degrees of tilt and twist character. These structural variations suggest one potential explanation for the reduced effective coupling area, although the correlation is not unambiguous.
Date: July 1, 1995
Creator: Miller, D.J.; Steel, D.G.; Yuan, F.; Hettinger, J.D.; Gray, K.E.; Talvacchio, J. et al.
Partner: UNT Libraries Government Documents Department