Download or read book Single Spin Asymmetries in Semi inclusive DIS at CLAS written by D. S. Hwang and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spin Asymmetries for Exclusive and Semi exclusive Reactions with CLAS written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An extensive experimental program to measure the spin structure of the nucleons is being carried out with the CLAS detector at Jefferson Lab using a longitudinally polarized electron beam incident on a longitudinally polarized target. Spin degrees of freedom offer new tools to explore the baryon structure and test the many theoretical approaches that attempt to characterize it, such as effective Lagrangian models and transverse momentum dependent parton distributions. I will present preliminary results for single and double spin asymmetries for exclusive [pi][sup 0], [pi][sup +], and [eta] electroproduction in the resonance region compared with unitary isobar and dynamical models, as well as [rho] electroproduction for DIS kinematics. I will also report on an analysis of the semi-inclusive and exclusive channels where double and single spin asymmetries were used to study transverse momentum dependent parton distributions.
Download or read book Proceedings of the International Congress on Comparative Physiology written by and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Single Spin Asymmetries in Electroproduction at CLAS written by Latifa Elouadrhiri and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present measurements of spin asymmetries in semi-inclusive processes in hard scattering kinematics using a 5.7 GeV electron beam and the CEBAF Large Acceptance Spectrometer (CLAS) at JLab. Scattering of longitudinally polarized electrons of an unpolarized liquid-hydrogen and off a polarized NH{sub 3} targets was studied over a wide range of kinematics. Non-zero single-beam and single-target spin asymmetries have been observed in semi-inclusive pion production in hard-scattering kinematics (Q{sup 2}> 1.2 GeV{sup 2}, W{sup 4}> 4 GeV{sup 2}). Systematic studies of factorization of x and z dependences have been done for different spin-dependent and spin-independent observables. No significant x/z dependence has been observed within statistical uncertainties, which is consistent with factorization of hard scattering and fragmentation processes.
Download or read book Transversity and SIDIS at CLAS written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The single-spin asymmetries (SSA) in semi-inclusive DIS have emerged as a powerful tool to access transverse momentum distributions of partons and to give access to the spin-orbit correlations. SSA enable measurements of some essentially unexplored physical observables, including transversity, {\it time-reversal odd} distribution and fragmentation functions. In this talk we present an overview of the latest studies of transverse spin effects and discuss newly released results, ongoing activities, as well as planned near term and future measurements of spin-orbit correlations at CLAS.
Download or read book Single Spin Asymmetries at CLAS written by Latifa Elouadrhiri and published by . This book was released on 2003 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present recent results from Jefferson Lab's CLAS detector on beam and target single-spin asymmetries in single pion electroproduction off unpolarized hydrogen and polarized NH 3 targets. Non-zero single-beam and single-target spin asymmetries are observed for the first time in semi-inclusive and exclusive pion production in hard-scattering kinematics.
Download or read book Mon roman policier n 152 written by and published by . This book was released on 1951 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Single Spin Asymmetries at CLAS written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Single spin asymmetries (SSA) are crucial tools in the study of the spin structure of hadrons in pion electroproduction, since they are directly related to some hot topics, including transverse polarization distribution functions, fragmentation of polarized quarks and generalized parton distribution functions. At low beam energies, when the virtual photon has a relatively large angle with respect to the initial spin direction, the measured single-target spin-dependent sin [phi] moment in the cross section for the longitudinally polarized target contain contributions from the target spin components, both longitudinal and transverse with respect to the photon direction. This contribution presents preliminary results from Jefferson Lab's CLAS detector on beam and target SSA in pion azimuthal distributions in one particle inclusive electroproduction in the DIS regime (Q2> 1GeV 2,W> 2GeV) off a polarized NH3 target.
Download or read book Single Spin Asymmetries in Semi inclusive Deep Inelastic Scattering and Drell Yan Processes written by and published by . This book was released on 2013 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: We examine in detail the diagrammatic mechanisms which provide the change of sign between the single transverse spin asymmetries measured in semi-inclusive deep inelastic scattering (SIDIS) and in the Drell-Yan process (DY). This asymmetry is known to arise due to the transverse spin dependence of the target proton combined with a T-odd complex phase. Using the discrete symmetry properties of transverse spinors, we show that the required complex phase originates in the denominators of rescattering diagrams and their respective cuts. For simplicity, we work in a model where the proton consists of a valence quark and a scalar diquark. We then show that the phases generated in SIDIS and in DY originate from distinctly different cuts in the amplitudes, which at first appears to obscure the relationship between the single-spin asymmetries in the two processes. Nevertheless, further analysis demonstrates that the contributions of these cuts are identical in the leading-twist Bjorken kinematics considered, resulting in the standard sign-flip relation between the Sivers functions in SIDIS and DY. Physically, this fundamental, but yet untested, prediction occurs because the Sivers effect in the Drell-Yan reaction is modified by the initial-state "lensing" interactions of the annihilating antiquark, in contrast to the final-state lensing which produces the Sivers effect in deep inelastic scattering.
Download or read book Precise Measurements of Beam Spin Asymmetries in Semi Inclusive pi 0 Production written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial sin [Phi]h amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle [Phi]h of the produced neutral pion. The dependence of this amplitude on Bjorken x and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations.
Download or read book PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP ENTITLED SINGLE SPIN ASYMMETRIES VOLUME 75 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Single-transverse spin asymmetries (SSA) in strong interactions have a long history, starting from the 1970s and 1980s when surprisingly large single-transverse spin asymmetries were observed in p+p [yields] [pi]X and pp [yields] [Lambda] + X, where really none were expected. They have again attracted much interest in recent years from both experimental and theoretical sides. In particular, first measurements by the STAR, PHENIX, and BRAHMS collaborations at RHIC have now become available which again reveal large single transverse spin asymmetries for hadron production in polarized proton proton scattering. This extends the SSA observations from the fixed target energy range to the collider regime. Meanwhile, experimental studies in Deep Inelastic Scattering by the HERMES collaboration at DESY, SMC at CERN, and CLAS at JLab also show a remarkably large SSA in semi-inclusive hadron production, [gamma]*p [yields] [pi]X, when the proton is transversely polarized. On the theoretical side, there are several approaches to understanding SSA within Quantum Chromodynamics (QCD). For example, to explain the large SSAs for hadron production in hadron collisions, a mechanism that takes into account the contribution from quark-gluon-quark correlations (twist-3) in the nucleon was proposed. On the other hand, possible origins of SSA in DIS and hadronic scattering were also found in leading-twist transverse momentum dependent parton distributions. Current theoretical efforts aim at a better conceptual understanding of these two types of mechanisms, and of their connections. We were very happy at this timely date to bring together the theorists and experimentalists of this field to review and discuss the current theoretical status and the latest experimental results. The whole workshop contained 25 formal talks, both experiment (15) and theory (10), and a few informal talks and many fruitful discussions. The topics covered all the relevant SSA observables, including in Deep Inelastic Scattering, the Drell-Yan process, and in inclusive hadron production and dijet correlations at hadron colliders. There were not only discussions on possible interpretations of the existing SSA data, but also on the future observables for the ongoing experiments as well as for planned experiments (such as RHIC II and eRHIC). On the theory side, the talks ranged from overviews and descriptions of the fundamental aspects of SSAs, to presentations of detailed phenomenological studies. All of the talks attracted much interest and initiated active discussions. Directions for future measurements were pointed out, in particular for studies at RHIC. Also, significant theoretical advances were made that may tie together some of the currently proposed mechanisms for single-spin asymmetries. This was a very successful workshop. It stimulated many discussions and new collaborations.
Download or read book Single Spin Asymmetries in Charged Pion Production from Semi Inclusive Deep Inelastic Scattering on a Transversely Polarized 3 He Target written by and published by . This book was released on 2011 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report the first measurement of target single spin asymmetries in the semi-inclusive $^3{He}(e, e'\pi^\pm)X$ reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0.14 $
Download or read book Spin Azimuthal Asymmetries in DIS at CLAS written by Harut Avakian and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present latest measurements of beam and target single-spin asymmetries in the single pion electroproduction in the DIS. In addition to significant target single-spin asymmetries the CLAS detector at Jlab also measures a significant beam-spinasymmetry when the analysis is restricted to events for which the pion carries a large fraction of the virtual photon momentum.
Download or read book Transverse Spin Physics written by Vincenzo Barone and published by World Scientific. This book was released on 2003 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 2. 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.
Download or read book Transversity 2005 written by Dr. Vincenzo Barone and published by World Scientific. This book was released on 2006 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: The notion of transversity in hadronic physics has been with us for over 25 years. Intriguing though it might have been, for much of that time transversity remained an intangible and remote object, of interest principally to a few theoreticians. In recent years transversity and transverse-spin effects in general have grown as both theoretical and experimental areas of active research. This increasing attention has now matured into a thriving field with a driving force of its own. The ever-growing bulk of data on asymmetries in collisions involving transversely polarised hadrons demands a more solid and coherent theoretical basis for its description. Indeed, it now appears rather clear that transversity and other closely related properties play a significant role in such phenomena.As part of a Ministry-funded inter-university Research Project, this workshop was organised to gather together experimentalists and theoreticians engaged in investigating the nature of transverse spin in hadronic physics, with the intent of favouring the exchange of up-to-date theoretical and experimental ideas and news on the subject. Over 70 physicists took part and very nearly all the major experiments involved in transverse-spin studies were officially represented, as too were the main theory groups working in the field. New results and new analyses sparked many interesting and lively discussions.
Download or read book UNIQUE DESCRIPTION FOR SINGLE TRANSVERSE SPIN ASYMMETRIES IN DIS AND HADRONIC COLLISIONS written by F. YUAN and published by . This book was released on 2006 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Gdh 2004 Proceedings Of The Third International Symposium On The Gerasimov drell hearn Sum Rule And Its Extensions written by Sebastian Kuhn and published by World Scientific. This book was released on 2005-02-21 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents an overview of the many new and exciting results, both theoretical and experimental, in the area of spin structure functions and sum rules at low to moderate photon virtuality Q2. It includes contributions from many leading scientists in the field worldwide.The volume covers the following topics:• recent results on the Gerasimov-Drell-Hearn (GDH) sum rule with real photons and its extensions to virtual photons• inclusive spin structure functions at low to moderate Q2 and their moments• exclusive measurements of nucleon spin structure in the resonance region• spin polarizabilities and Compton scattering• chiral perturbation theory and other low-energy limits of QCD• lattice QCD, duality, and phenomological models• nuclear effects and the GDH sum rule in nuclei• experimental techniques (polarized targets and beams)• future plans and projects
