Lattice QCD and Nucleon Resonances

Lattice QCD and Nucleon Resonances PDF Author: R. G. Edwards
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Lattice calculations provide an ab initio means for the study of QCD. Recent progress at understanding the spectrum and structure of nucleons from lattice QCD studies is reviewed. Measurements of the masses of the lightest particles for the lowest spin values are described and related to predictions of quark model. The determination of the masses of the higher masses is described, and in particular the mass of the Roper resonance, using Bayesian statistics. The need to perform calculations at realistically light values of the pion mass is emphasized, and the exciting progress at attaining such masses is outlined. The talk concludes with future prospects, emphasizing the importance of constructing a basis of interpolating operators that is sensitive both the three-quark and to multi-quark and excited glue.

Lattice QCD and Nucleon Resonances

Lattice QCD and Nucleon Resonances PDF Author: R. G. Edwards
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Lattice calculations provide an ab initio means for the study of QCD. Recent progress at understanding the spectrum and structure of nucleons from lattice QCD studies is reviewed. Measurements of the masses of the lightest particles for the lowest spin values are described and related to predictions of quark model. The determination of the masses of the higher masses is described, and in particular the mass of the Roper resonance, using Bayesian statistics. The need to perform calculations at realistically light values of the pion mass is emphasized, and the exciting progress at attaining such masses is outlined. The talk concludes with future prospects, emphasizing the importance of constructing a basis of interpolating operators that is sensitive both the three-quark and to multi-quark and excited glue.

Threshold Resonances - a Lattice Perspective

Threshold Resonances - a Lattice Perspective PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 5

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Book Description
The calculation of the masses of the lightest nucleon resonances using lattice QCD is surveyed. Recent results for the mass of the First radial excitation of the nucleon, the Roper resonance, are reviewed and the interpretation in terms of models of hadronic structure, such as the quark model and multi-quark states, discussed. The talk concludes with an outline of prospects for future calculations.

Structure of Nucleon Excited States from Lattice QCD

Structure of Nucleon Excited States from Lattice QCD PDF Author: Finn M. Stokes
Publisher: Springer Nature
ISBN: 3030257223
Category : Science
Languages : en
Pages : 237

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Book Description
Quantum Chromodynamics (QCD) describes the interactions between elementary quarks and gluons as they compose the nucleons at the heart of atomic structure. The interactions give rise to complexity that can only be examined via numerical simulations on supercomputers. This work provides an introduction to the numerical simulations of lattice QCD and establishes new formalisms relevant to understanding the structure of nucleons and their excited states. The research opens with an examination of the non-trivial QCD vacuum and the emergence of “centre domains.” The focus then turns to establishing a novel Parity-Expanded Variational Analysis (PEVA) technique solving the important problem of isolating baryon states moving with finite momentum. This seminal work provides a foundation for future calculations of baryon properties. Implementation of the PEVA formalism discloses important systematic errors in conventional calculations and reveals the structure of nucleon excited states from the first principles of QCD for the first time.

Nucleon Structure from Lattice QCD.

Nucleon Structure from Lattice QCD. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Recent advances in lattice field theory, in computer technology and in chiral perturbation theory have enabled lattice QCD to emerge as a powerful quantitative tool in understanding hadron structure. I describe recent progress in the computation of the nucleon form factors and moments of parton distribution functions, before proceeding to describe lattice studies of the Generalized Parton Distributions (GPDs). In particular, I show how lattice studies of GPDs contribute to building a three-dimensional picture of the proton, I conclude by describing the prospects for studying the structure of resonances from lattice QCD.

NSTAR 2004

NSTAR 2004 PDF Author: Jean-Paul Bocquet
Publisher: World Scientific
ISBN: 981270227X
Category : Science
Languages : en
Pages : 427

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Book Description
This book covers recent advances in the field of nucleon resonances presented at the IX International Workshop on the Physics of Excited Baryons, NSTAR2004. A complete overview of the most recent experimental results obtained worldwide on baryon spectroscopy is presented together with theoretical progress on related topics ranging from resonance parameters extraction to lattice-QCD calculations through effective field theory. Of particular interest, a large part of the book is devoted to exotic states with quantum numbers of pentaquarks, whose recent discovery represents a new chapter in hadronic physics. The proceedings have been selected for coverage in: . OCo Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings). OCo CC Proceedings OCo Engineering & Physical Sciences."

Excited Nucleons And Hadron Structure - Proceedings Of The Nstar 2000 Conference

Excited Nucleons And Hadron Structure - Proceedings Of The Nstar 2000 Conference PDF Author: Volker Burkert
Publisher: World Scientific
ISBN: 9814542709
Category : Science
Languages : en
Pages : 454

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Book Description
The conference NSTAR 2000 was part of a series of conferences and workshops that began in New York in 1988. Since then, the field of excited nucleons and hadron structure has developed enormously, and the scope has broadened. Most significantly, new experimental facilities have come into operation, allowing precise measurements of resonance couplings and transition form factors. The search for “missing” quark model states and gluonic excitations in complex hadronic channels is now possible.On the theory side, new and promising developments have emerged: quark models with meson degrees of freedom, hybrid baryon models, and studies of baryons in the limit of many colors. For the first time, lattice QCD has been employed to calculate masses of excited nucleons. Nucleon resonances are now recognized as providing significant contributions to the nucleon spin sum rules, as well as the Gerasimov-Drell-Hearn and Bjorken integrals, at finite momentum transfer.

Lattice QCD for Nuclear Physics

Lattice QCD for Nuclear Physics PDF Author: Huey-Wen Lin
Publisher: Springer
ISBN: 3319080229
Category : Science
Languages : en
Pages : 255

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Book Description
With ever increasing computational resources and improvements in algorithms, new opportunities are emerging for lattice gauge theory to address key questions in strongly interacting systems, such as nuclear matter. Calculations today use dynamical gauge-field ensembles with degenerate light up/down quarks and the strange quark and it is possible now to consider including charm-quark degrees of freedom in the QCD vacuum. Pion masses and other sources of systematic error, such as finite-volume and discretization effects, are beginning to be quantified systematically. Altogether, an era of precision calculation has begun and many new observables will be calculated at the new computational facilities. The aim of this set of lectures is to provide graduate students with a grounding in the application of lattice gauge theory methods to strongly interacting systems and in particular to nuclear physics. A wide variety of topics are covered, including continuum field theory, lattice discretizations, hadron spectroscopy and structure, many-body systems, together with more topical lectures in nuclear physics aimed a providing a broad phenomenological background. Exercises to encourage hands-on experience with parallel computing and data analysis are included.

Nstar 2001 - Proceedings Of The Workshop On The Physics Of Excited Nucleons

Nstar 2001 - Proceedings Of The Workshop On The Physics Of Excited Nucleons PDF Author: Dieter Drechsel
Publisher: World Scientific
ISBN: 9814490040
Category : Baryons
Languages : en
Pages : 528

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Book Description
The study of N∗s can provide us with critical insights into the nature of QCD in the confinement domain. The keys to progress in this domain are the identification of its important degrees of freedom and the effective forces between them. The nucleon is the simplest system in which the nonabelian character of QCD is manifest. There are Nc quarks in a baryon because there are Nc colors, and as a consequence Gell-Mann and Zweig were forced to introduce the quarks in order to describe the octet and decuplet baryons.This volume gives a status report on the recent experimental and theoretical results in the field of nucleon resonance physics. A wealth of new high precision data was presented from facilities around the world, such as BES, BNL, ELSA, GRAAL, JLab, MAMI, MIT/Bates, SPring8, and Yerevan. Particular emphasis was laid on polarization degrees of freedom and large acceptance detectors as precision tools for studying small but important transition amplitudes, and the helicity (spin) structure of the nucleon. There were new results describing the nucleon resonance structure on the basis of quantum chromodynamics, either directly in terms of quarks and gluons by means of lattice gauge theory, or in terms of hadrons in the framework of chiral field theories. A status report on duality showed the surprising connections between the physics of the low energy nucleon resonance region and the realm of quark structure functions in deep inelastic scattering. Finally, this volume contains a summary report of the BRAG workshop, devoted to the analysis of baryon resonances.

Even Parity Excitations of the Nucleon in Lattice QCD.

Even Parity Excitations of the Nucleon in Lattice QCD. PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 4510

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Book Description
We study the spectrum of the even parity excitations of the nucleon in quenched lattice QCD. We extend our earlier analysis by including an expanded basis of nucleon interpolating fields, increasing the physical size of the lattice, including more configurations to enhance statistics and probing closer to the chiral limit. With a review of world lattice data, we conclude that there is little evidence of the Roper resonance in quenched lattice QCD.

$N^*$ Resonances in Lattice QCD from (mostly) Low to (sometimes) High Virtualities

$N^*$ Resonances in Lattice QCD from (mostly) Low to (sometimes) High Virtualities PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
I present a survey of calculations of the excited $N^*$ spectrum in lattice QCD. I then describe recent advances aimed at extracting the momentum-dependent phase shifts from lattice calculations, notably in the meson sector, and the potential for their application to baryons. I conclude with a discussion of calculations of the electromagnetic transition form factors to excited nucleons, including calculations at high $Q^2$.