Download or read book Generalized Transverse Momentum Dependent Parton Distributions of the Nucleon written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present first results from our analysis of the most general quark-quark correlator of the nucleon, which can be parameterized in terms of so-called generalized transverse momentum dependent parton distributions. These results include the first complete parameterization of the nucleon GPDs and TMDs to all twists as well as new results on possible nontrivial relations between them.

Download or read book Structure and Spin of the Nucleon written by and published by . This book was released on 2014 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Parton distribution functions, describing longitudinal momentum, helicity and transversity distributions of quarks and gluons, have been recently generalized to account also for transverse degrees of freedom. Two new sets of more general distributions, Transverse Momentum Distributions and Generalized Parton Distributions, were introduced to describe transverse momentum and space distributions of partons. Great progress has been made since then in measurements of different Single Spin Asymmetries (SSAs) in semi-inclusive and hard exclusive processes providing access to TMDs and GPDs, respectively. Facilities world-wide involved in studies of the 3D structure of nucleon include HERMES, COMPASS, BELLE, BaBar, Halls A, B, and C at JLab, and PHENIX and STAR at RHIC (BNL). TMD studies in the Drell-Yan process are also becoming an important part of the program of hadron scattering experiments. Studies of TMDs are also among the main driving forces of the JLab 12-GeV upgrade project, several of the forward upgrade proposals of STAR and PHENIX at RHIC, and future facilities, such as the Electron Ion Collider (EIC), FAIR in Germany, and NICA in Russia. In this contribution we present an overview of the latest developments in studies of parton distributions and discuss newly released results, ongoing activities, as well as some future measurements.

Download or read book Generalized Parton Distributions in Nuclei written by Swadhin k Taneja and published by . This book was released on 2006 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nucleon Transverse Momentum dependent Parton Distributions from Domain Wall Fermion Calculations at 297 MeV Pion Mass written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Lattice QCD calculations of transverse momentum-dependent parton distributions (TMDs) in a nucleon are performed based on a definition of TMDs via hadronic matrix elements of quark bilocal operators containing staple-shaped gauge connections. A parametrization of the matrix elements in terms of invariant amplitudes serves to cast them in the Lorentz frame preferred for the lattice calculation. Using a RBC/UKQCD domain wall fermion ensemble corresponding to a pion mass of 297MeV, on a lattice with spacing 0.084fm, selected TMD observables are accessed and compared to previous explorations at heavier pion masses on coarser lattices.

Download or read book Generalized Parton Distributions and Angular Momentum Decomposition of the Nucleon written by Hikmat Bahadur BC and published by . This book was released on 2010 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transverse momentum dependent Parton Distributions in a Spectator Diquark Model written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Within the framework of a spectator diquark model of the nucleon, involving both scalar and axial-vector diquarks, we calculate all the leading-twist transverse-momentum-dependent parton distribution functions (TMDs). Naive Time-odd densities are generated through a one-gluon-loop rescattering mechanism, simulating the final state interactions required for these functions to exist. Analytic results are obtained for all the TMDs, and a connection with the light-cone wave functions formalism is also established. The model parameters are fixed by reproducing the phenomenological parametrizations of unpolarized and helicity parton distributions at the lowest available scale. Predictions for the other parton densities are given and, whenever possible, compared with available parametrizations.

Download or read book Transverse Momentum Distributions Inside the Nucleon from Lattice QCD written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We study transverse momentum dependent parton distribution functions (TMDs) with non-local operators in lattice QCD, using MILC/LHPC lattices. Results obtained with a simplified operator geometry show visible dipole deformations of spin-dependent quark momentum densities. We discuss the basic concepts of the method, including renormalization of the gauge link, and an extension to a more elaborate operator geometry that would allow us to analyze process-dependent TMDs such as the Sivers-function.

Download or read book Studies of the 3D Structure of the Nucleon at Jlab written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of the 3D structure of the nucleon encoded in Transverse Momentum Dependent distribution and fragmentation functions of partons and Generalized Parton Distributions are among the key objectives of the JLab 12 GeV upgrade and the Electron Ion Collider. Main challenges in extracting 3D partonic distributions from precision measurements of hard scattering processes include clear understanding of leading twist QCD fundamentals, higher twist effects, and also correlations of hadron production in target and current fragmentation regions. In this contribution we discuss some ongoing studies and future measurements of spin-orbit correlations at Jefferson Lab.

Download or read book Moments of Nucleon Spin dependent Generalized Parton Distributions written by Thomas Lippert and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a lattice measurement of the first two moments of the spin-dependent GPD H-tilde(x, xi, t). From these we obtain the axial coupling constant and the second moment of the spin-dependent forward parton distribution. The measurements are done in full QCD using Wilson fermions. In addition, we also present results from a first exploratory study of full QCD using Asqtad sea and domain-wall valence fermions.

Download or read book Semi Inclusive DIS and Transverse Momentum Dependent Distribution Studies at CLAS written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Transverse Momentum Dependent parton distribution functions were introduced to describe both longitudinal and transverse momentum distributions of partons inside a nucleon. Great progress has been made in recent years in understanding these distributions measuring different spin asymmetries in semi-inclusive processes. Here we present an overview of the ongoing studies at CLAS and programs planned for the 6 and 12 GeV activity.

Download or read book Nucleon Form Factors from Generalized Parton Distributions written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We discuss the links between Generalized Parton Distributions (GPDs) and elastic nucleon form factors. These links, in the form of sum rules, represent powerful constraints on parameterizations of GPDs. A Regge parameterization for GPDs at small momentum transfer, is extended to the large momentum transfer region and it is found to describe the basic features of proton and neutron electromagnetic form factor data. This parameterization is used to estimate the quark contribution to the nucleon spin.

Download or read book Generalized Parton Distributions and Their Covariant Extension written by Nabil Chouika and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Generalized Parton Distributions (GPDs) encode the correlations between longitudinal momentum and transverse position of partons inside hadrons and can give access to a picture of the nucleon structure in 2+1 dimensions. They have been studied theoretically and experimentally for almost two decades and a new experimental era is starting (at JLab and COMPASS currently, and in the future at an EIC) to extract them. The difficulty is that only an indirect experimental access is so far possible, through different exclusive channels and various observables. Therefore, one has to take into account the many theoretical constraints to be able to produce accurate models and rely on their phenomenology. Two important constraints are called the polynomiality and positivity properties. The approach of this thesis is to make use of both of them by first modeling low Fock states light-front wave-functions, which gives a GPD in the DGLAP region by a parton number conserved overlap, and then covariantly extending this GPD to the ERBL region, through an inverse radon transform. In fine, the goal is to apply this on a constituent quark-like model for valence GPDs, which would allow to produce a phenomenological output (on DVCS data for instance) from this kind of models, which was impossible before. We make use of the versatile PARTONS framework to achieve this under various perturbative QCD assumptions.

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 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 Transverse Momentum Dependent Parton Distribution Functions with Domain Wall Valence Fermions written by and published by . This book was released on 2011 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transverse Momentum Dependent Parton Distribution Functions (TMDs) reveal the intrinsic motion of quarks inside the nucleon. They are essential ingredients needed to understand angular asymmetries studied in SIDIS experiments, including current and planned experiments at JLab. Within a class B proposal, we ask for time on the Jefferson Lab computer cluster to extract amplitudes for TMDs from existing lattice QCD gauge configurations and propagators calculated by the USQCD/MILC/LHP collaborations [Aubin 2004, Bratt 2010]. The proposal encompasses more comprehensive studies with a simplified operator [Haegler 2010] along with more realistic and more demanding calculations that promise to give access to time reversal odd TMDs such as the Sivers function. We ask for cluster computer time equivalent to 1.26 million J/Psi core hours, plus disk and tape storage worth 159000 J/Psi core hours.

Download or read book Nucleon Form Factors Generalized Parton Distributions and Quark Angular Momentum written by Markus Diehl and published by . This book was released on 2013 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transverse Parton Structure of the Nucleon and the Black disk Limit in High energy Scattering written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The transverse spatial distribution of partons in the nucleon (generalized parton distributions) is a crucial ingredient in the description of high-energy ep and pp scattering with hard QCD processes. Experimental information about the transverse spatial distribution of gluons comes from measurements of the t-dependence of J/psi production at HERA and other processes. We discuss the physical mechanisms leading to a growth of the nucleon's transverse size at small x. Based on this information, we study the interaction of small-size color dipoles with the proton in the leading log Q2 approximation. We find that at small x and central impact parameters the dipole-nucleon interaction approaches the unitarity, or black-disk (BDL) limit. We argue that this new regime of strong interactions can be probed in central pp collisions at LHC.