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 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 Neutron Spin Structure Studies and Low Energy Tests of the Standard Model at JLab written by and published by . This book was released on 2008 with total page 54514 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most recent results on the spin structure of the neutron from Hall A are presented and discussed. Then, an overview is given of various experiments planned with the 12 GeV upgrade at Jefferson Lab to provide sensitive tests of the Standard Model at relatively low energies.

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 Results from JLab Hall A written by Zein-Eddine Meziani and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: My presentation will focus on some of the latest results of the neutron spin physics program at Jefferson Laboratory in Hall A using a polarized 3He target. This program includes several completed experiments in which the spin structure functions of 3He were measured. The covered kinematic regions were these measurements were performed include the low Q2 resonance and inelastic regions and the high Q2 deep inelastic region. These experiments offer a ground for testing our understanding of the strong regime of quantum chromodynamics (QCD) through the determination of the neutron spin-dependent structure functions and their moments.

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: Recent progress from Jefferson Lab has significantly improved our understanding of the nucleon spin structure in the high-x region. Results from two experiments in Hall A are presented. The first experiment is a precision measurement of the neutron spin asymmetry, A1(superscript n), in the high-x (valence quark) region. The results show for the first time that A1(superscript n) becomes positive at large x, strongly breaking SU(6) (spin-flavor) symmetry. The data trend is in good agreement with SU(6)-breaking valence quark models and with the fits to the previous world data. Combining the A1(superscript n) results with the world A1(superscript n) data, the up and down quark spin distributions in the nucleon were extracted. The results showed that for the proton the valence down quark spin is in the opposite direction from that of the proton, in disagreement with predictions of leading-order perturbative QCD models, which neglect quark orbital angular momentum.

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 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 Jefferson Lab Physics Overview written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: I review highlights of the Jefferson Lab nucleon structure program. I shall emphasize recent results from experiments exploring the spin structure of the nucleon and from dedicated experiments aimed at accessing the generalized parton distributions (GPDs).

Download or read book Nucleon Spin Structure Study at Jefferson Lab written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: I will first review the latest development in the nucleon spin structure study with lepton- nucleon deep inelastic scattering (DIS) from high energy laboratories. I will then concentrate on the progress and plan of study of the nucleon spin structure in the low energy region. With the newly built high luminosity 6 GeV electron beam accelerator and the progress in the highly polarized electron source and highly polarized targets, new experiments are being carried out at Jefferson Lab (CEBAF) to study the nucleon spin structure in the resonance region at low Q2, with focus on the generalized GDH sum rule. Some preliminary results are presented. A generalized GDH sum rule study could provide a first comparison of experimental data with calculations from a fundamental theory over the entire Q2 regime. Taking advantage of the high luminosity of Jefferson Lab, selected spin structure experiments in the DIS region are also planned, concentrating in the valence quark region and the stud y of the quark-gluon correlations through higher twist effects. The parton-hadron duality provides the link between the DIS and the resonance region. Experimental study of duality in spin structure is planned. Outlook of spin structure study with a future 12 GeV energy upgraded Jefferson Lab is discussed.

Download or read book New Results on Nucleon Spin Structure written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent precision spin structure data from Jefferson Lab have significantly advanced our knowledge of nucleon structure in the valence quark (high-x) region and improved our understanding of higher-twist effects, spin sum rules and quark-hadron duality. First, results of a precision measurement of the neutron spin asymmetry, A[sub 1][sup n], in the high-x region are discussed. The new data shows clearly, for the first time, that A[sub 1][sup n] becomes positive at high x. They provide crucial input for the global fits to world data to extract polarized parton distribution functions. Preliminary results on A[sub 1][sup p] and A[sub 1][sup d] in the high-x region have also become available. The up and down quark spin distributions in the nucleon were extracted. The results for [Delta]d/d disagree with the leading-order pQCD prediction assuming hadron helicity conservation. Then, results of a precision measurement of the g[sub 2][sup n] structure function to study higher-twist effects are presented. The data show a clear deviation from the lead-twist contribution, indicating a significant higher-twist (twist-3 or higher) effect. The second moment of the spin structure functions and the twist-3 matrix element d[sub 2][sup n] results were extracted at a high Q[sup 2] of 5 GeV[sup 2] from the measured A[sub 2][sup n] in the high-x region in combination with existing world data and compared with a Lattice QCD calculation. Results for d[sub 2][sup n] at low-to-intermediate Q[sup 2] from 0.1 to 0.9 GeV[sup 2] were also extracted from the JLab data. In the same Q[sup 2] range, the Q[sup 2] dependence of the moments of the nucleon spin structure functions was measured, providing a unique bridge linking the quark-gluon picture of the nucleon and the coherent hadronic picture. Sum rules and generalized forward spin polarizabilities were extracted and compared with Chiral Perturbation Theory calculations and phenomenological models. Finally, preliminary results on the resonance spin structure functions in the Q[sup 2] range from 1 to 4 GeV[sup 2] were presented, which, in combination with DIS data, will enable a detailed study of the quark-hadron duality in spin structure functions.

Download or read book The Spin Structure Of The Nucleon written by Bernard Frois and published by World Scientific. This book was released on 1998-02-24 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt: From its early beginnings at SLAC in the 1970's, the study of nucleon spin structure using polarized lepton beams and polarized nucleon targets has become increasingly important in nuclear and particle physics, with current experiments at several of the world's high energy and nuclear physics laboratories (CERN, DESY, SLAC and Jefferson Lab) and with enormous related theoretical studies. The understanding of the fascinating but complicated problem of nucleon spin structure has progressed substantially, but fundamental questions remain and it can be confidently predicted that future activity will be high.The Erice Course on The Spin Structure of the Nucleon covered both the experimental and theoretical aspects of the subject, and this volume includes the lectures given at the School. In many cases the lecture material has been extended and updated by the authors. In addition, several recent publications on experimental work have been added in an appendix.

Download or read book Spin Physics in Hall A of 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: Two recent experiments in Hall A of Jefferson Lab have explored the spin structure of the neutron. Experiment E99-117 focused on measuring the neutron spin asymmetry A1(superscript n) to high precision at x = 0.33, 0.47 and 0.60 and Q2 = 2.7, 3.5 and 4.8 (GeV/c)2, respectively. A second experiment, E97-103, measured the polarized spin structure function g2(superscript n) at x (almost equal to) 0.2 for five values of the momentum transfer Q2 from 0.58 to 1.36 (GeV/c)2. Preliminary results from these experiments will be presented and compared to theoretical models.

Download or read book Jefferson Lab s Results on the Q2 evolution of Moments of Spin Structure Functions written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the recent JLab measurements on moments of spin structure functions at intermediate and low Q2. The Bjorken sum and Burkhardt-Cottingham sum on the neutron are presented. The later appears to hold. Higher moments (generalized spin polarizabilities and d2(superscript n)) are shown and compared to chiral perturbation theory and lattice QCD respectively.

Download or read book Neutron Structure New Results with CLAS at Jefferson Lab written by Sebastian Kuhn and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: New measurements using the 6 GeV continuous electron beam and the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab have collected information on the form factors and the unpolarized structure functions of the neutron, with minimal uncertainty from nuclear binding effects. One experiment has also tried to measure these binding effects more directly, using the method of ''spectator tagging''. These experiments are forerunners for an extensive program with the energy-upgraded 12 GeV accelerator at Jefferson Lab.

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.