Download or read book Probing Generalized Parton Distributions with Jefferson Lab at 12 GeV written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We discuss plans for Jefferson Lab to explore GPDs in hard exclusive reactions. A broad experimental program is proposed with up to 11 GeV polarized electron beams. Such an upgraded CEBAF, with high precision, and high performance detectors, will be a suitable place to study deep virtual production of mesons and photons in the range of Q2

Download or read book The Generalized Parton Distribution Program After the Jefferson Lab 12 GeV Upgrade written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Generalized Parton Distribution framework was introduced in the late 90's and describes the nucleon in a revolutionary way, correlating the information from both momentum and transverse position space into experimentally accessible functions. After a brief introduction, this article reviews the Jefferson Lab 6 GeV measurements of Deeply Virtual Compton Scattering in Halls A and B, which give a unique access to Generalized Parton Distributions (GPD). The second half of this article reviews the Jefferson Lab 12 GeV upgrade in general terms, and then focuses on the GPD program in Halls A and B. This second generation of experiments will yield more accurate, more complete data in a wider kinematical range than any experiment ever before, using the full capability of a higher beam energy, higher luminosities, upgraded detectors and refined extraction techniques.

Download or read book Study of Generalized Parton Distributions with CLAS at Jefferson Lab written by and published by . This book was released on 2002 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The program to study the Generalized Parton Distributions in deeply exclusive processes with CLAS at Jefferson Lab is discussed.

Download or read book The Generalized Parton Distribution Program at Jefferson Lab written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent results on the Generalized Parton Distribution (GPD) program at Jefferson Lab (JLab) will be presented. The emphasis will be in the Hall A program aiming at measuring Q^2-dependences of different terms of the Deeply Virtual Compton Scattering (DVCS) cross section. This is a fundamental step before one can extract GPD information from JLab DVCS data. The upcoming program in Hall A, using both a 6 GeV beam (2010) and a 11 GeV beam (~2015) will also be described.

Download or read book The Generalized Parton Distribution Program in Hall A at Jefferson Lab written by and published by . This book was released on 2008 with total page 13357 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent results on the Generalized Parton Distribution (GPD) program at Jefferson Lab (JLab) will be presented. The emphasis will be in the Hall A program aiming at measuring Q2â dependences of different terms of the Deeply Virtual Compton Scattering (DVCS) cross section. This is a fundamental step before one can extract GPD information from JLab DVCS data. Neutral pion production will also be discussed and results from the CLAS collaboration will be shown. Finally, the upcoming program in Hall A, using both a 6 GeV beam ([approximate]2010) and a 11 GeV beam ([approximate]2015) will be described.

Download or read book Deeply Virtual Compton Scattering at Jefferson Lab written by Frédéric Georges and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduced in the mid 90's, Generalized Parton Distributions (GPDs) are now a key element in the study of the nucleon internal structure. GPDs are a generalization of Form Factors and Parton Distribution Functions. They encapsulate both spatial and momentum distributions of partons inside a nucleon, allowing to perform its three-dimensional tomography. Furthermore, they allow to derive the total orbital angular momentum of quarks through the Ji sum rule, which is a crucial point to unravel the nucleon spin structure. By providing a more complete description of hadrons in terms of quarks and gluons, a deeper understanding of Quantum Chromodynamics can be reached.GPDs are experimentally accessible through deeply exclusive electro-production processes, and one of the simplest channels available is Deeply Virtual Compton Scattering (DVCS). A worldwide experimental program was started in the early 2000's to extract these GPDs. The DVCS experiment E12-06-114 performed at Jefferson Laboratory Hall A (Virginia, USA) between 2014 and 2016, is encompassed in this program. The aim of this experiment is to extract with high precision the DVCS helicity-dependent cross sections as a function of the momentum transfer Q2, for fixed values of the Bjorken variable xBj, on a proton target. The recent upgrade of the accelerator facility to 12 GeV allows to cover a larger Q2 range than in previous measurements and probe yet unexplored kinematic regions, while the polarized electron beam allows the separation of the contributions from the real and imaginary parts of the DVCS amplitude to the total cross section. In this document, a brief summary of the worldwide experimental program for the study of GPDs will be provided, followed by a description of the E12-06-114 apparatus and data analysis. Finally, the results of the unpolarized and polarized cross-section measurements are presented and compared to a few selected models.

Download or read book Generalized Parton Distributions and Deep Exclusive Reactions written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We review briefly the physical concept of generalized parton distributions and the experimental challenges associated with the corresponding measurements of deep exclusive reactions. The first data obtained at Jefferson Lab for exclusive photon (DVCS) and vector meson (DVMP) electroproduction above the resonance-excitation region are described. Two upcoming dedicated DVCS experiments are presented in some detail.

Download or read book Study of Generalized Parton Distributions and Deeply Virtual Compton Scattering on the Nucleon with the CLAS and CLAS12 Detectors at the Jefferson Laboratory written by and published by . This book was released on 2012 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The exclusive leptoproduction of a real photon is considered to be the "cleanest" way to access the Generalized Parton Distribution (GPD). This process is called Deeply Virtual Compton Scattering (DVCS) lN 2!lN[gamma], and is sensitive to all the four GPDs. Measuring the DVCS cross section is one of the main goals of this thesis. In this thesis, we present the work performed to extract on a wide phase-space the DVCS cross-section from the JLab data at a beam energy of 6 GeV.

Download or read book An Introduction to the Generalized Parton Distributions written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The concepts of Generalized Parton Distributions (GPD) are reviewed in an introductory and phenomenological fashion. These distributions provide a rich and unifying picture of the nucleon structure. Their physical meaning is discussed. The GPD are in principle measurable through exclusive deeply virtual production of photons (DVCS) or of mesons (DVMP). Experiments are starting to test the validity of these concepts. First results are discussed and new experimental projects presented, with an emphasis on this program at Jefferson Lab.

Download or read book Generalized Parton Distributions and Depp Exclusive Reactions written by Michel Garcon and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We review briefly the physical concept of generalized parton distributions and the experimental challenges associated with the corresponding measurements of deep exclusive reactions. The first data obtained at Jefferson Lab for exclusive photon (DVCS) and vector meson (DVMP) electroproduction above the resonance-excitation region are described. Two upcoming dedicated DVCS experiments are presented in some detail.

Download or read book Exclusive Processes at JLab at 6 GeV written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Deeply virtual exclusive reactions provide a unique opportunity to probe the complex internal structure of the nucleon. They allow to access information about the correlations between parton transverse spatial and longitudinal momentum distributions from experimental observables. Dedicated experiments to study Deeply Virtual Compton Scattering (DVCS) and Deeply Virtual Meson Production (DVMP) have been carried out at Jefferson Lab using continuous electron beam with energies up to 6 GeV. Unpolarized cross sections, beam, target and double spin asymmetries have been measured for DVCS as well as for [pi]0 exclusive electroproduction. The data from Hall B provide a wide kinematic coverage with Q2=1-4.5 GeV2, xB=0.1-0.5, and -t up to 2 GeV2. Hall A data have limited kinematic range partially overlapping with Hall B kinematics but provide a high accuracy measurements. Scaling tests of the DVCS cross sections provide solid evidence of twist-2 dominance, which makes chiral-even GPDs accessible even at modest Q2. We will discuss the interpretation of these data in terms of Generalized Parton Distributions (GPDs) model. Successful description of the recent CLAS [pi]0 exclusive production data within the framework of the GPD-based model provides a unique opportunity to access the chiral-odd GPDs.

Download or read book Probing Nucleons And Nuclei In High Energy Collisions Proceedings Of The Int Program Int 18 3 written by Alexei Prokudin and published by World Scientific. This book was released on 2020-05-29 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains proceedings of the 7-week INT program dedicated to the physics of the Electron-Ion Collider (EIC), the world's first polarized electron-nucleon (ep) and electron-nucleus (eA) collider to be constructed in the United States. The 2015 NSAC Long Range Plan recommended EIC as the 'highest priority for new facility construction following the completion of FRIB'. The primary goal of the EIC is to establish precise multi-dimensional imaging of quarks and gluons inside nucleons and nuclei. This includes (i) understanding the spatial and momentum space structure of the nucleon through the studies of TMDs (transverse-momentum-dependent parton distributions), GPD (generalized parton distributions) and the Wigner distribution; (ii) determining the partonic origin of the nucleon spin; (iii) exploring the new quantum chromodynamics (QCD) frontier of ultra-strong gluon fields, with the potential to seal the discovery of a new form of dense gluon matter predicted to exist in all nuclei and nucleons at small Bjorken x — the parton saturation.The program brought together both theorists and experimentalists from Jefferson Lab (JLab), Brookhaven National Laboratory (BNL) along with the national and international nuclear physics communities to assess and advance the EIC physics.

Download or read book Deeply Virtual Exclusive Processes and Generalized Parton Distributions written by and published by . This book was released on 2011 with total page 12006 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of the comprehensive program in Deeply Virtual Exclusive Scattering at Jefferson Laboratory is to create transverse spatial images of quarks and gluons as a function of their longitudinal momentum fraction in the proton, the neutron, and in nuclei. These functions are the Generalized Parton Distributions (GPDs) of the target nucleus. Cross section measurements of the Deeply Virtual Compton Scattering (DVCS) reaction ep 2!ep[gamma] in Hall A support the QCD factorization of the scattering amplitude for Q^2 e"2 GeV^2. Quasi-free neutron-DVCS measurements on the Deuteron indicate sensitivity to the quark angular momentum sum rule. Fully exclusive H(e, e'p[gamma]) measurements have been made in a wide kinematic range in CLAS with polarized beam, and with both unpolarized and longitudinally polarized targets. Existing models are qualitatively consistent with the JLab data, but there is a clear need for less constrained models. Deeply virtual vector meson production is studied in CLAS. The 12 GeV upgrade will be essential for for these channels. The [rho] and [omega] channels reactions offer the prospect of flavor sensitivity to the quark GPDs, while the [phi]-production channel is dominated by the gluon distribution.

Download or read book Generalized Parton Distributions from Hadronic Observables written by Saeed Ahmad and published by . This book was released on 2008 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New Results And Actual Problems In Particle Astroparticle Physics And Cosmology Proceedings Of Xxixth International Workshop On High Energy Physics written by Roman Anatolievich Ryutin and published by World Scientific. This book was released on 2014-03-26 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique volume contains the materials of the XXIXth International Workshop on High Energy Physics. The content of the volume is much wider than just high-energy physics and actually concerns all the most fundamental areas of modern physics research: high-energy physics proper, gravitation and cosmology. Presentations embrace both theory and experiment.

Download or read book Generalized Parton Distributions from Deep Virtual Compton Scattering at CLAS written by and published by . This book was released on 2010 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, we have analyzed the beam spin asymmetry and the longitudinally polarized target spin asymmetry of the Deep Virtual Compton Scattering process, recently measured by the Jefferson Lab CLAS collaboration. Our aim is to extract information about the Generalized Parton Distributions of the proton. By fitting these data, in a largely model-independent procedure, we are able to extract numerical values for the two Compton Form Factors $H_{Im}$ and $\tilde{H}_{Im}$ with uncertainties, in average, of the order of 30%.

Download or read book Exclusive Electroproduction of Strange Mesons with JLab 12 GeV written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We summarize the physics topics which can be addressed by measurements of high-Q^2 exclusive electroproduction of strange mesons, gamma* N -> phi N, K* Lambda, K Lambda, K Sigma, at Jefferson Lab with 11 GeV beam energy. The proposed investigations are aimed both at exploring the reaction mechanism (dominance of point-like configurations) and extracting information about baryon structure from the data (generalized parton distributions, or GPDs). They include (a) probing the t-dependence of the nucleon's gluon GPD (transverse spatial distribution of gluons) in phi meson production; (b) separating the nucleon helicity-flip and nonflip quark GPDs in K* Lambda production with measurement of the Lambda recoil polarization; (c) probing strangeness polarization in the nucleon in K Lambda and K Sigma production. These studies rely only on the analysis of cross section ratios, which are less affected by the theoretical uncertainties of present GPD-based calculations than absolute cross sect.