Download or read book Neutron Transversity at Jefferson Lab written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nucleon transversity and single transverse spin asymmetries have been the recent focus of large efforts by both theorists and experimentalists. On-going and planned experiments from HERMES, COMPASS and RHIC are mostly on the proton or the deuteron. Presented here is a planned measurement of the neutron transversity and single target spin asymmetries at Jefferson Lab in Hall A using a transversely polarized 3He target. Also presented are the results and plans of other neutron transverse spin experiments at Jefferson Lab. Finally, the factorization for semi-inclusive DIS studies at Jefferson Lab is discussed.
Download or read book Neutron Transversity Measurement at Jefferson Lab with a Polarized He 3 Target written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A first measurement of single target spin asymmetry (SSA) from semi-inclusive electroproduction of charged pions from a transversely polarized 3He target in deep-inelastic-scattering kinematics will take data in Hall A at Jefferson Lab in 2008. Such SSA will allow for an extraction of the much desired information on the Collins and Sivers asymmetry from the "neutron" in order to probe the quark transversity distributions. The experiment will be a coincidence measurement with the BigBite spectrometer detecting the scattered electrons and the left-arm HRS spectrometer detecting the charged pions. The prospect of future 11 GeV measurements at Jefferson Lab in Hall A using a solenoid magnetic detector system is also discussed in this talk.
Download or read book Neutron Spin Structure Study at Jefferson Lab Hall A written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: With a high-intensity highly-polarized 6 GeV electron beam, and a high-density polarized 3He target, we have carried out a number of experiments to study the neutron spin structure at Hall A in Jefferson Lab. Taking advantage of the high luminosity of Jefferson Lab, we completed two inclusive deep-inelastic-scattering experiments this summer. In the first, precision measurements were made of the spin asymmetry A(superscript n)1 in the valence quark (high Bjorken x) region; and in the second, higher-twist effects were studied via precision measurements of g(superscript n)2. Physics motivation and preliminary results from the first experiment will be presented and discussed. I will also present nearly final results from an earlier experiment, which measured the generalized GDH sum for the neutron in the Q2 range of 0.1 to 1 GeV2. Planned near-term experiments will be briefly discussed.
Download or read book Precision Measurements of the Neutron Spin Structure at Jefferson Lab Hall A written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors present here recent progress on the experimental study of the neutron spin structure at Jefferson Lab Hall A. They focus on two precision experiments. The physics motivation and the experimental setup will be described first. Then they present results for the neutron spin asymmetry A1(superscript n) and results for spin-flavor decomposition of the nucleon spin in the valence quark region, and preliminary results for the neutron spin structure function g2(superscript n) at low Q2.
Download or read book Neutron Spin Structure Measurements in JLab Hall A written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recently, the high polarized luminosity available at Jefferson Lab (JLab) has allowed the study of the nucleon spin structure at an unprecedented precision, enabling us to access the hard-to-reach valence quark (high-x) region and also to accurately map the intermediate to low Q2 region. The high-x region is of special interest, because this is where the valence quark contributions are expected to dominate. With sea quarks and explicit gluon contributions expected not to be important, it is a clean region to test our understanding of nucleon structure.
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 An Overview of Recent Nucleon Spin Structure Measurements at Jefferson Lab written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Jefferson Lab have made significant contributions to improve our knowledge of the longitudinal spin structure by measuring polarized structure functions, g1 and g2, down to Q2 = 0.02 GeV2. The low Q2 data is especially useful in testing the Chiral Perturbation theory (cPT) calculations. The spin-dependent sum rules and the spin polarizabilities, constructed from the moments of g1 and g2, provide an important tool to study the longitudinal spin structure. We will present an overview of the experimental program to measure these structure functions at Jefferson Lab, and present some recent results on the neutron polarizabilities, proton g1 at low Q2, and proton and neutron d2 measurement. In addition to this, we will discuss the transverse spin structure of the nucleon which can be accessed using chiral-odd transversity distribution (h1), and show some results from measurements done on polarized 3He target in Hall A.
Download or read book Precision Exploration of Neutron Spin Structure at Jefferson Lab written by Nilanga Liyanage and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Spin structure functions provide basic information about the spin of the quark distributions inside the nucleon. Experimental understanding of the nucleon spin in the kinematic region where the three basic (''valence'') quarks dominate the nucleon wave function is still rather poor. Jefferson lab, with its high quality, high polarization continuous electron beam, and a high density polarized 3He target in experimental Hall A, provides the ideal opportunity to gather neutron spin structure data in the valence region with unprecedented precision. Two high precision neutron spin structure measurements were completed in Hall A last summer. The first experiment measured the spin asymmetry A1(N) in the valence region while in second experiment higher-twist effects were studied via measurements of gn2. The planed upgrade of Jefferson lab CEBAF accelerator to 12 GeV will significantly increase the accessible kinematic range and the precision of these measurements.
Download or read book The First Measurement of Neutron Transversity on a Transversely Polarized 3He Target written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We recently measured the neutron target single spin asymmetry in the semi-inclusive deep inelastic 3He (e, e', pi+/- )X reactions with a transversely polarized 3He target. The experiment was performed in Hall A at Jefferson Lab from October 2008 to February 2009. Pions were detected in the high-resolution spectrometer in coincidence with scattered electrons detected by the BigBite spectrometer. The kinematic coverage focuses on the valence quark region, x = 0.1 - 0.4, at Q2 = 1-3 (GeV/c)2. With good particle identifications using a RICH detector and an aerogel Cherenkov counter, data on kaons were obtained at the same time. The data from this experiment, when combined with the world data, will provide constraints on the Transversity and Sivers distributions on both u-quark and d-quark in the valence quark region.
Download or read book Studies of the Neutron Spin Structure at Jefferson Lab written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The polarized 3He program of Hall A at Jefferson Lab will be described. Results on the generalized Gerasimov-Drell-Hearn integral for the neutron in a Q2 range between 0.02 GeV2/c2
Download or read book Unveiling the Nucleon Tensor Charge at Jefferson Lab written by and published by . This book was released on 2017 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, future experiments at the Jefferson Lab 12 GeV upgrade, in particular, the Solenoidal Large Intensity Device (SoLID), aim at a very precise data set in the region where the partonic structure of the nucleon is dominated by the valence quarks. One of the main goals is to constrain the transversity quark distributions. We apply recent theoretical advances of the global QCD extraction of the transversity distributions to study the impact of future experimental data from the SoLID. Especially, we develop a model-independent method based on the hessian matrix analysis that allows to estimate the uncertainties of the transversity quark distributions and their tensor charge contributions extracted from the pseudo-data for the SoLID. Both u and d-quark transversity distributions are shown to be very well constrained in the kinematical region of the future experiments with the proton and the effective neutron targets.
Download or read book Results and Future Perspectives of the Neutron Spin Structure Studies at Jefferson Lab written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Jefferson Lab Hall A polarized 3He (neutron spin structure) program is presented with a special focus on the measurement of the Q2 evolution of the generalized GDH integral.
Download or read book The G13 Experiment at Jefferson Lab written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Strangeness has been shown to be important for the understanding of the so-called missing resonances. Due to the scarce experimental data in strangeness photoproduction on the neutron, phenomenological models such as coupled-channels analyses resort to certain approximations that do not allow getting either accuracy or agreement between different analyses when extracting resonance parameters. Thus, in order to obtain high-quality data on the neutron channels, a new experiment (designated g13), based on a liquid deuterium target and a polarized photon beam (both circular and linear polarization) covering from threshold to 2.3 GeV has been done at the Thomas Jefferson National Accelerator Facility. In this paper, a brief description of the g13 experiment is given.
Download or read book Jefferson Lab s Journey Into the Nucleus written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The year 1969 saw the publication of the first results indicating that hard scattering centres exist deep inside protons. A collaboration between the Stanford Linear Accelerator Center (SLAC) and the Massachusetts Institute of Technology was using SLAC's new high-energy electron LINAC to pioneer a rich new field in the study of the nucleus--deep inelastic scattering. Their measurements revealed that nucleons are made up of point-like particles, which Richard Feynman dubbed ''partons''. Thirty-five years on, studies of the parton-nature of the nucleus continue, not only at the traditional high-energy centres, but also at lower-energy laboratories, and in particular at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Virginia. Jefferson Lab is home to the Continuous Electron Beam Accelerator Facility (CEBAF). Its main mission is to explore the atomic nucleus and the fundamental building-blocks of matter. As part of this mission, researchers there study the transition from the picture of the nucleus as a bound state of neutrons and protons to its deeper structure in terms of quarks and gluons--in other words, the transition from the hadronic degrees of freedom of nuclear physics to the quark-gluon degrees of freedom of high-energy physics. In exploring this transition, a wide range of experiments has been performed, from measurements of elastic form factors at large momentum transfers to studies of deep inelastic scattering. An array of spectrometers together with electron-beam energies of up to 5.7 GeV has allowed the laboratory to make significant contributions to this field. This article describes three experiments, each aimed at improving our understanding of a different aspect of the partonic nature of matter. The first, a classic deep inelastic scattering experiment, seeks to further our understanding of the composition of nucleon spin. The second experiment studies the concept of quark-hadron duality--a link between the deep inelastic region and the resonance region. The third experiment uses the atomic nucleus as a laboratory to improve understanding of the propagation and hadronization of quarks. Jefferson Lab's ability to perform this range of measurements is illustrated by the plot from the CEBAF Large Acceptance Spectrometer (CLAS) shown on the cover of this magazine, where the hadronic resonance peaks are seen to be washed out as one goes from the delta resonance around 1.2 GeV to higher invariant masses and into the deep inelastic scattering realm of quarks and gluons.
Download or read book Exclusive Processes at High Momentum Transfer written by A. V. Radyushkin and published by World Scientific. This book was released on 2002 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the physics of exclusive processes at high momentum transfer and their description in terms of generalized parton distributions, perturbative QCD, and relativistic quark models. It covers recent developments in the field, both theoretical and experimental. Contents: Perspectives on Exclusive Processes in QCD (S J Brodsky); High-t Meson Photo- and Electroproduction: A Window on Partonic Structure of Hadrons (J-M Laget); Nucleon Hologram with Exclusive Leptoproduction (A Belitsky & D Muller); QCD Factorization for the Pion Diffractive Dissociation into Two Jets (D Yu Ivanov); GPDs, Form Factors and Compton Scattering (P Kroll); Real Compton Scattering from the Proton (A Nathan); Resonance Exchange Contributions to Wide-Angle Compton Scattering: The D-Term (T Oppermann); Proton-Antiproton Annihilation into Two Photons at Large s (C Weiss); Quark--Hadron Duality Studies at Jefferson Lab; An Overview of New and Exisiting Results (C Keppel); Novel Hard Semiexclusive Processes and Color Singlet Clusters in Hadrons (M Strikman et al.); and other papers. Readership: Theoretical and experimental researchers in nuclear and elementary particle physics.
Download or read book Recent Results of Target Single Spin Asymmetry Experiments at Jefferson Lab written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We report recent results from Jefferson Lab Hall A "Neutron Transversity" experiment (E06-010). Transversely polarized target single-spin asymmetry AUT and beam-target double-spin asymmetry A{sub LT} have been measured in semi-inclusive deep-inelastic scattering (SIDIS) reactions on a polarized neutron (3He) target. Collins-type and Sivers-type asymmetries have been extracted from A{sub UT} for charged pion SIDIS productions, which are sensitive to quark transversity and Sivers distributions, correspondingly. Double spin asymmetry A{sub LT} is sensitive to a specific quark transverse momentum dependent parton distribution (TMD), the so-called "transverse helicity" (g{sub 1T}) distributions. In addition, target single-spin asymmetries A{sub y} in inclusive electron scattering on a transversely polarized 3He target in quasi-elastic and deep inelastic kinematics were also measured in Hall A.
Download or read book Transverse Spin Structure of the Nucleon Through Target Single Spin Asymmetry in Semi Inclusive Deep Inelastic e E prime pi pm Reaction at Jefferson Lab written by and published by . This book was released on 2011 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Jefferson Lab (JLab) 12 GeV energy upgrade provides a golden opportunity to perform precision studies of the transverse spin and transverse-momentum-dependent structure in the valence quark region for both the proton and the neutron. In this paper, we focus our discussion on a recently approved experiment on the neutron as an example of the precision studies planned at JLab. The new experiment will perform precision measurements of target Single Spin Asymmetries (SSA) from semi-inclusive electro-production of charged pions from a 40-cm long transversely polarized $^3$He target in Deep-Inelastic-Scattering kinematics using 11 and 8.8 GeV electron beams. This new coincidence experiment in Hall A will employ a newly proposed solenoid spectrometer (SoLID). The large acceptance spectrometer and the high polarized luminosity will provide precise 4-D ($x$, $z$, $P_T$ and $Q^2$) data on the Collins, Sivers, and pretzelocity asymmetries for the neutron through the azimuthal angular dependence. The full 2$\pi$ azimuthal angular coverage in the lab is essential in controlling the systematic uncertainties. The results from this experiment, when combined with the proton Collins asymmetry measurement and the Collins fragmentation function determined from the e$^+$e$^-$ collision data, will allow for a quark flavor separation in order to achieve a determination of the tensor charge of the d quark to a 10% accuracy. The extracted Sivers and pretzelocity asymmetries will provide important information to understand the correlations between the quark orbital angular momentum and the nucleon spin and between the quark spin and nucleon spin.
