Download or read book Future Measurements of Deeply Virtual Compton Scattering at HERMES written by and published by . This book was released on 2001 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Future Measurements of Deeply Virtual Compton Scattering written by V. A. Korotkov and published by . This book was released on 2001 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Deeply Virtual Compton Scattering at HERA written by and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deeply Virtual Compton Scattering Results Future written by Wolf-Dieter Nowak and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Measurement of Deeply Virtual Compton Scattering and Its T dependence at HERA written by and published by . This book was released on 2007 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deeply Virtual Compton Scattering at 6 GeV written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors propose a measurement of the Deep Virtual Compton Scattering process (DVCS) ep → ep[gamma] in Hall A at Jefferson Lab with a 6 GeV beam. The authors are able to explore the onset of Q2 scaling, by measuring a beam helicity asymmetry for Q2 ranging from 1.5 to 2.5 GeV2 at x{sub B} ≈ 0.35. At this kinematics, the asymmetry is dominated by the DVCS Bethe-Heitler (BH) interference, which is proportional to the imaginary part of the DVCS amplitude amplified by the full magnitude of the BH amplitude. The imaginary part of the DVCS amplitude is expected to scale early. Indeed, the imaginary part of the forward Compton amplitude measured in deep inelastic scattering (via the optical theorem) scales at Q2 as low as 1 GeV2. If the scaling regime is reached, they make an 8% measurement of the skewed parton distributions (SPD) contributing to the DVCS amplitude. Also, this experiment allows them to separately estimate the size of the higher-twist effects, since they are only suppressed by an additional factor 1/Q compared to the leading-twist term, and have a different angular dependence. They use a polarized electron beam and detect the scattered electron in the HRSe, the real photon in an electromagnetic calorimeter (under construction) and the recoil proton in a shielded scintillator array (to be constructed). This allows them to determine the difference in cross-sections for electrons of opposite helicities. This observable is directly linked to the SPD's. The authors estimate that 25 days of beam (600 hours) are needed to achieve this goal.
Download or read book Measurement of Deeply Virtual Compton Scattering at HERA written by Rainer Stamen and published by . This book was released on 2001 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Measurement of the Q2 W and T dependences of Deeply Virtual Compton Scattering at HERA written by ZEUS Collaboration and published by . This book was released on 2008 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deeply Virtual Compton Scattering at Jefferson Laboratory written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The generalized parton distributions (GPDs) have emerged as a universal tool to describe hadrons in terms of their elementary constituents, the quarks and the gluons. Deeply virtual Compton scattering (DVCS) on a proton or neutron ($N$), $e N \rightarrow e' N' \gamma$, is the process more directly interpretable in terms of GPDs. The amplitudes of DVCS and Bethe-Heitler, the process where a photon is emitted by either the incident or scattered electron, can be accessed via cross-section measurements or exploiting their interference which gives rise to spin asymmetries. Spin asymmetries, cross sections and cross-section differences can be connected to different combinations of the four leading-twist GPDs (${H}$, ${E}$, ${\tilde{H}}$, ${\tilde{E}}$) for each quark flavors, depending on the observable and on the type of target. This paper gives an overview of recent experimental results obtained for DVCS at Jefferson Laboratory in the halls A and B. Several experiments have been done extracting DVCS observables over large kinematics regions. Multiple measurements with overlapping kinematic regions allow to perform a quasi-model independent extraction of the Compton form factors, which are GPDs integrals, revealing a 3D image of the nucleon.
Download or read book Measurement of Deeply Virtual Compton Scattering Using the ZEUS Detector at HERA written by Iwona Grabowska-Bold and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Future Directions In Quark Nuclear Physics Proceedings Of The Workshop written by Anthony W Thomas and published by World Scientific. This book was released on 1999-04-01 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most fundamental questions in understanding strong interaction is whether or not quarks and gluons play a significant role in nuclear systems. At high densities we need to explore the existence and nature of a deconfinement phase transition. At lower densities we wish to study the changes in the properties of a hadron particle as mass and electroweak form factors, when it is immersed in nuclear matter. Finally, we may even ask whether the internal structure of the nucleon plays a role in the binding and properties of finite nuclei.On the theoretical side the issues raised here are of concern to a very broad community, from those working in traditional many-body physics, to those building effective field theories, to those working in lattice QCD. Experimentally, there are many accelerators, mature, new and planned, which can offer insight into this field — from SLAC to HERA, COSY, CELSIUS and TJNAF. This workshop brought together key figures from all areas of theoretical and experimental physics concerned with this fundamental problem.
Download or read book DIFFRACTION 2002 Interpretation of the New Diffractive Phenomena in Quantum Chromodynamics and in the S Matrix Theory written by R. Fiore and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Research Workshop, Alushta, Crimea, Ukraine, from 31 August to 6 September 2002
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 Three dimensional Partonic Structure of the Nucleon written by Mauro Anselmino and published by IOS Press. This book was released on 2012 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: The three-dimensional nucleon structure is central to many theoretical and experimental activities, and research in this field has seen many advances in the last two decades, addressing fundamental questions such as the orbital motion of quarks and gluons inside the nucleons, their spatial distribution, and the correlation between spin and intrinsic motion. A real three-dimensional imaging of the nucleon as a composite object, both in momentum and coordinate space, is slowly emerging.This book presents lectures and seminars from the Enrico Fermi School Three-Dimensional Partonic Structure of the Nucleon, held in Varenna,
Download or read book SoLID SIDIS written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past few decades, investigations of the nucleon structure mainly focused on the one dimensional study of parton distributions and structure functions. New theoretical developments, including both transverse momentum distributions (TMDs) [1, 2] and generalized parton distributions (GPDs) [3, 4], provide a new way to understand the 3 dimensional structure of the nucleon. TMDs give access to the nucleon tomography in the momentum space and also provide an opportunity to evaluate the contribution of quarks' and gluons' orbital angular momenta to the nucleon spin. The experimental study of TMDs requires a device with high luminosity, large kinematic coverage and great detection resolutions. With the Jefferson Lab (JLab) 12 GeV electron beam, we have proposed a Solenoidal Large Intensity Device (SoLID) [5] in Hall A which is capable of performing such measurements. Several newly approved experiments[6, 7, 8] will perform measurements of both the single and double spin asymmetries via semi-inclusive deep inelastic scattering (SIDIS) from polarized 3He ("neutron") and proton targets [9]. The new data will provide important information to extract TMDs with unprecedented precision. Besides, we are also able to use SoLID to explore many more important physics topics. Several experiments for the measurements of PVDIS [10] and J=y production [11] have been approved and new proposals are under development. For example, with the similar SIDIS configuration, we are actively developing new measurements to study GPDs via deep virtual Compton scattering (DVCS) with polarized targets, doubly-DVCS, deep virtual meson production, time-like Compton scattering [12], and so on. Our collaboration has submitted the pre-conceptual design report [5] to JLab and successfully passed the Director's Review in early 2015. Our collaborators are focusing on optimizing the detector system, finalizing the detector designs and proceeding on the detector R & D. We are looking forward to having the DOE Science Review in the near future.
Download or read book Deeply Virtual Compton Scattering at JLab Hall A written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The deeply virtual Compton scattering reaction has been investigated in the Hall A of the Jefferson Laboratory by measuring longitudinally polarized (e, e'gamma) cross sections, in the valence quark region, for protons and neutrons. In the proton channel, experimental results strongly support the factorization of the cross section at Q2 as low as 2 GeV2, opening the path to systematic measurements of generalized parton distributions (GPDs). In the neutron case, preliminary data show sensitivity to the angular momentum of quarks.
Download or read book Hadron Physics written by I.J. Douglas MacGregor and published by CRC Press. This book was released on 2006-07-07 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt: Straddling the traditional disciplines of nuclear and particle physics, hadron physics is a vital and extremely active research area, as evidenced by a 2004 Nobel prize and new research facilities, such as that scheduled to open at CERN. Scientifically it is of vital importance in extrapolating our knowledge of quark-gluon physics at the sub-nucleon level to provide a wider perspective of strongly interacting hadrons, which make up the vast bulk of known matter in the Universe. Through detailed, pedagogical chapters contributed by key international experts, Hadron Physics maps out our contemporary knowledge of the subject. It covers both the theoretical and experimental aspects of hadron structure and properties along with a wide range of specific research topics, results, and applications. Providing a full picture of activity in the field, the book highlights three particular areas of current research: computational lattice hadron physics, the structure and dynamics of hadrons, and generalized parton distributions. It provides a solid introduction, includes background theory, and presents the current state of understanding of the subject.
