The Pion Form Factor and Momentum and Angular Momentum Fractions of the Proton in Lattice QCD

The Pion Form Factor and Momentum and Angular Momentum Fractions of the Proton in Lattice QCD PDF Author: Gen Wang
Publisher:
ISBN:
Category :
Languages : en
Pages : 90

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The Pion Form Factor and Momentum and Angular Momentum Fractions of the Proton in Lattice QCD

The Pion Form Factor and Momentum and Angular Momentum Fractions of the Proton in Lattice QCD PDF Author: Gen Wang
Publisher:
ISBN:
Category :
Languages : en
Pages : 90

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Exploring Proton Structure Using Lattice QCD

Exploring Proton Structure Using Lattice QCD PDF Author: Dru Bryant Renner
Publisher:
ISBN:
Category :
Languages : en
Pages : 444

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We calculate moments of the generalized parton distributions of the nucleon using lattice QCD. The generalized parton distributions determine the angular momentum decomposition of the nucleon and the transverse distributions of partons within the nucleon. Additionally, the generalized parton distributions reduce to the elastic form factors and ordinary parton distributions in particular kinematic limits. Thus by calculating moments of the generalized parton distributions in lattice QCD we can explore many facets of the structure of the nucleon. In this effort, we have developed the building block method to determine all the lattice correlation functions which con- tribute to the off forward matrix elements of the twist two operators. These matrix elements determine the generalized form factors of the nucleon which in turn give the moments of the generalized parton distributions. Thus we use our building block method to calculate all the matrix elements of the lowest twist two operators. Fur- thermore, we use our method to construct an overdetermined set of matrix elements allowing a more accurate calculation of the generalized form factors.

Quarks, Nuclei And Stars: Memorial Volume Dedicated For Gerald E Brown

Quarks, Nuclei And Stars: Memorial Volume Dedicated For Gerald E Brown PDF Author: Jeremy W Holt
Publisher: World Scientific
ISBN: 9813220678
Category : Science
Languages : en
Pages : 537

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Book Description
This memorial volume is dedicated to physicist Gerald E Brown (1926-2013) or 'Gerry' as he was known to his many students, postdocs, colleagues and friends. As written by one of the contributors to this book, 'Gerry was an inspiring father figure for generations of theoretical nuclear physicists and a great human being'.This book covers a wide range of topics in nuclear physics, including nuclear structure, two- and three-body nuclear forces, strangeness nuclear physics, chiral symmetry, hadrons in dense medium, hidden local symmetry, heavy quark symmetry, cosmic neutrinos, nuclear double-beta decay, neutron stars, gravitational waves, renormalization group methods, exotic nuclei, electron ion collider (EIC), and much more. Most of the authors are Gerry's former students and collaborators.We hope readers will find this book very interesting not only for its physics content but also for the window it gives into Gerry's personal legacy and humanity. This book has vivid recollections of Gerry at Stony Brook, Princeton and Copenhagen, together with his humor and his very special intuitive way of thinking.

Lattice QCD Calculation of Nucleon Structure

Lattice QCD Calculation of Nucleon Structure PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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It is emphasized in the 2015 NSAC Long Range Plan [1] that \understanding the structure of hadrons in terms of QCD's quarks and gluons is one of the central goals of modern nuclear physics." Over the last three decades, lattice QCD has developed into a powerful tool for ab initio calculations of strong-interaction physics. Up until now, it is the only theoretical approach to solving QCD with controlled statistical and systematic errors. Since 1985, we have proposed and carried out rst-principles calculations of nucleon structure and hadron spectroscopy using lattice QCD which entails both algorithmic development and large scale computer simulation. We started out by calculating the nucleon form factors { electromagnetic [2], axial-vector [3], NN [4], and scalar [5] form factors, the quark spin contribution [6] to the proton spin, the strangeness magnetic moment [7], the quark orbital angular momentum [8], the quark momentum fraction [9], and the quark and glue decomposition of the proton momentum and angular momentum [10]. These rst round of calculations were done with Wilson fermions in the `quenched' approximation where the dynamical e ects of the quarks in the sea are not taken into account in the Monte Carlo simulation to generate the background gauge con gurations. Beginning in 2000, we have started implementing the overlap fermion formulation into the spectroscopy and structure calculations [11, 12]. This is mainly because the overlap fermion honors chiral symmetry as in the continuum. It is going to be more and more important to take the symmetry into account as the simulations move closer to the physical point where the u and d quark masses are as light as a few MeV only. We began with lattices which have quark masses in the sea corresponding to a pion mass at 300 MeV and obtained the strange form factors [13], charm and strange quark masses, the charmonium spectrum and the Ds meson decay constant fDs [14], the strangeness and charmness [15], the meson mass decomposition [16] and the strange quark spin from the anomalous Ward identity [17]. Recently, we have started to include multiple lattices with di erent lattice spacings and di erent volumes including large lattices at the physical pion mass point. We are getting quite close to being able to calculate the hadron structure at the physical point and to do the continuum and large volume extrapolations which is our ultimate aim. We have now nished several projects which have included these systematic corrections. They include the leptonic decay width of the [18], the N sigma and strange sigma terms [19], and the strange quark magnetic moment [20]. Over the years, we have also studied hadron spectroscopy with lattice calculations and in phenomenology. These include Roper resonance [21, 22], pentaquark state [23], charmonium spectrum [24, 14], glueballs [25, 26, 27, 28], scalar mesons a0(1450) and (600) [29] and other scalar mesons [30], and the 1+ meson [31]. In addition, we have employed the canonical approach to explore the rst order phase transition and the critical point at nite density and nite temperature [32, 33]. We have also discovered a new parton degree of freedom { the connected sea partons, from the path-integral formulation of the hadronic tensor [34, 35] which explains the experimentally observed Gottfried sum rule violation [34]. Combining experimental result on the strange parton distribution, the CT10 global tting results of the total u and d anti-partons and the lattice result of the ratio of the momentum fraction of the strange vs that of u or d in the disconnected insertion, we have shown that the connected sea partons can be isolated [36]. In this nal technical report, we shall present a few representative highlights that have been achieved in the project.

Pion Form Factor in Lattice QCD with Light Pions

Pion Form Factor in Lattice QCD with Light Pions PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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We present a recent calculation of the pion electromagnetic form factor in Lattice QCD with light (~300 MeV) dynamical pions. Our result is consistent with experimental data and the vector meson dominance (VMD) hypothesis up to momentum transfer of 4 GeV2.

The Spin Structure of the Proton

The Spin Structure of the Proton PDF Author: Steven D. Bass
Publisher: World Scientific
ISBN: 9812709460
Category : Science
Languages : en
Pages : 212

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Book Description
One of the main challenges in nuclear and particle physics in the last 20 years has been to understand how the proton's spin is built up from its quark and gluon constituents. Quark models generally predict that about 60% of the proton's spin should be carried by the spin of the quarks inside, whereas high energy scattering experiments have shown that the quark spin contribution is small - only about 30%. This result has been the underlying motivation for about 1000 theoretical papers and a global program of dedicated spin experiments at BNL, CERN, DESY and Jefferson Laboratory to map the individual quark and gluon angular momentum contributions to the proton's spin, which are now yielding exciting results. This book gives an overview of the present status of the field: what is new in the data and what can be expected in the next few years. The emphasis is on the main physical ideas and the interpretation of spin data. The interface between QCD spin physics and the famous axial U(1) problem of QCD (eta and etaprime meson physics) is also highlighted. Book jacket.

Nstar2007

Nstar2007 PDF Author: Hans W. Hammer
Publisher: Springer Science & Business Media
ISBN: 3540851445
Category : Science
Languages : en
Pages : 298

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c Societ` a Italiana di Fisica / Springer-Verlag 2008 The 11th Workshop on The Physics of Excited Nucleons, NSTAR 2007, was held at the University of Bonn, Germany,fromSeptember5–8,2007.ItwasthelatestofaseriesofsuccessfulconferencesattheRensselaerPolytechnic Institute (1988), Florida State University (1994 and 2005), Je?erson Lab (1995 and 2000), INT Seattle (1996), GWU ? Washington (1997), ECT Trento (1998), Mainz (2001), Pittsburgh (2002) and the LPSC Grenoble (2004). A Baryon Resonance Analysis Group (BRAG) meeting immediately before the workshop focused especially on the physical meaning of bare and dressed scattering matrix singularities. A focus workshop on? photoproduction rounded o? the NSTAR 2007. The goal of NSTAR 2007 was to bring together experts on all areas of physics relevant to baryon spectroscopy, both in experiment and theory. Latest results were presented in 30 plenary talks and 34 parallel contributions, the proceedings of which are collected in this volume. The workshop was attended by 123 scientists of 41 universities and laboratories from 16 countries. Exciting new high-precision data were shown from facilities in Asia, the US and Europe, e.g. BES, BNL, COSY, ELSA, GRAAL, JLab, MAMI and LEPS. Large-acceptance detectors provide complete angular distributions in many reaction channels. Particular emphasis is put on the measurement of single and double polarisation observables such that many new polarization measurements can be expected in forthcoming meetings.

Energy Research Abstracts

Energy Research Abstracts PDF Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 840

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The Pion Form Factor from Lattice QCD with Two Dynamical Flavours

The Pion Form Factor from Lattice QCD with Two Dynamical Flavours PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 17

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Exclusive Reactions At High Momentum Transfer - Proceedings Of The International Workshop

Exclusive Reactions At High Momentum Transfer - Proceedings Of The International Workshop PDF Author: Anatoly Radyushkin
Publisher: World Scientific
ISBN: 9814471518
Category : Science
Languages : en
Pages : 453

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Book Description
Exclusive reactions are becoming one of the major sources of information about the deep structure of nucleons and other hadrons. The 2007 International Workshop held at Jefferson Lab in Newport News, Virginia, USA — the world's leading facility performing research on nuclear, hadronic and quark-gluon structure of matter — focused on the application of a variety of exclusive reactions at high momentum transfer, utilizing unpolarized and polarized beams and targets, to obtain information about nucleon ground-state and excited-state structure at short distances. This is a subject which is central to the programs of current accelerators and especially planned future facilities.This proceedings volume contains, in concentrated form, information about the newest developments, both theoretical and experimental, in the study of hard exclusive reactions.