scholarly journals Hadron Structure from Lattice QCD

2006 ◽  
Vol 21 (04) ◽  
pp. 720-725 ◽  
Author(s):  
◽  
J. W. Negele ◽  
B. Bistrovic ◽  
R. G. Edwards ◽  
G. Fleming ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Transition Form Factor ◽  
Form Factors ◽  
Electromagnetic Form Factors ◽  
Transition Form ◽  
Hadron Structure ◽  
Interacting Particles ◽  
Axial Charge ◽  
Charge Structure ◽  
Quark Masses

The structure of neutrons, protons, and other strongly interacting particles is now being calculated in full, unquenched lattice QCD with quark masses entering the chiral regime. This talk describes selected examples, including the nucleon axial charge, structure functions, electromagnetic form factors, the origin of the nucleon spin, the transverse structure of the nucleon, and the nucleon to Delta transition form factor.

scholarly journals Nucleon and Δ electromagnetic form factors

2015 ◽  
Vol 39 ◽  
pp. 1560089
Author(s):  
Erik Bartoš ◽  
Stanislav Dubnička ◽  
Anna-Zuzana Dubničková
Keyword(s):  
Form Factor ◽  
Magnetic Dipole ◽  
Transition Form Factor ◽  
Form Factors ◽  
Dipole Transition ◽  
Nucleon Resonance ◽  
Electromagnetic Form Factors ◽  
Analytic Model ◽  
Transition Form ◽  
Measured Ratio

The unitary and analytic model for nucleons works very well. The model for spin [Formula: see text] baryons can predict static parameters for [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text]. We prepared the scheme how to construct the model also for [Formula: see text] nucleon resonance. It was used to describe transition form factor [Formula: see text] and the experimentally measured ratio [Formula: see text] with the help of relations for magnetic dipole transition and charge quadrupole form factors.

scholarly journals Recent highlights with baryons from lattice QCD

2020 ◽  
Vol 241 ◽  
pp. 02004
Author(s):  
Colin Morningstar
Keyword(s):  
Lattice Qcd ◽  
Percent Level ◽  
Form Factors ◽  
Distribution Functions ◽  
Electromagnetic Form Factors ◽  
Parton Distribution Functions ◽  
Quark Masses ◽  
Proton Mass ◽  
Key Points

Highlights from recent computations in lattice QCD involving baryons are presented. Calcula tions of the proton mass and spin decompositions are discussed, a percent level determination of the nucleon axial coupling is described, and determinations of the proton and neutron electromagnetic form factors and light-cone parton distribution functions are outlined. Recent results applying the so-called Luscher method to meson-baryon systems are presented. Key points emphasized are that much better precision with disconnected diagrams is being achieved, incorporating multi-hadron operators is now feasible, and more and more studies are being done with physical quark masses.

scholarly journals Light meson form factors at high Q2 from lattice QCD

2018 ◽  
Vol 175 ◽  
pp. 06015 ◽  
Author(s):  
Jonna Koponen ◽  
André Zimermmane-Santos ◽  
Christine Davies ◽  
G. Peter Lepage ◽  
Andrew Lytle
Keyword(s):  
Lattice Qcd ◽  
Theoretical Calculations ◽  
Light Quark ◽  
Form Factors ◽  
Hadron Structure ◽  
Strange Quarks ◽  
Pion Scattering ◽  
Quark Masses ◽  
Systematic Uncertainties ◽  
Atomic Electrons

Measurements and theoretical calculations of meson form factors are essential for our understanding of internal hadron structure and QCD, the dynamics that bind the quarks in hadrons. The pion electromagnetic form factor has been measured at small space-like momentum transfer |q2| < 0.3 GeV2 by pion scattering from atomic electrons and at values up to 2.5 GeV2 by scattering electrons from the pion cloud around a proton. On the other hand, in the limit of very large (or infinite) Q2 = −q2, perturbation theory is applicable. This leaves a gap in the intermediate Q2 where the form factors are not known. As a part of their 12 GeV upgrade Jefferson Lab will measure pion and kaon form factors in this intermediate region, up to Q2 of 6 GeV2. This is then an ideal opportunity for lattice QCD to make an accurate prediction ahead of the experimental results. Lattice QCD provides a from-first-principles approach to calculate form factors, and the challenge here is to control the statistical and systematic uncertainties as errors grow when going to higher Q2 values. Here we report on a calculation that tests the method using an ηs meson, a ’heavy pion’ made of strange quarks, and also present preliminary results for kaon and pion form factors. We use the nf = 2 + 1 + 1 ensembles made by the MILC collaboration and Highly Improved Staggered Quarks, which allows us to obtain high statistics. The HISQ action is also designed to have small dicretisation errors. Using several light quark masses and lattice spacings allows us to control the chiral and continuum extrapolation and keep systematic errors in check.

scholarly journals Recent progress on the study of nucleon structure from lattice QCD and future perspectives

2020 ◽  
Author(s):  
Constantia Alexandrou
Keyword(s):  
Lattice Qcd ◽  
Recent Progress ◽  
Form Factors ◽  
Distribution Functions ◽  
Nucleon Structure ◽  
Electromagnetic Form Factors ◽  
Momentum Fraction ◽  
Future Perspectives ◽  
Parton Distribution Functions ◽  
Quark Masses

We review the progress achieved within the last five years in the simulations of lattice QCD, as well as in the analysis for selected quantities probing nucleon structure. In particular, we discuss results on the nucleon electromagnetic form factors, \sigmaσ-terms, the momentum fraction carried by quark in the nucleon and the helicity and transversity moments. All quantities are obtained using simulations generated with quark masses fixed to their physical values. In addition, we review the on-going effort to extract parton distribution functions (PDFs) directly from lattice QCD using the quasi-PDF approach.

scholarly journals Electromagnetic transition form factors of baryons in a relativistic Faddeev approach

2018 ◽  
Vol 181 ◽  
pp. 01013 ◽  
Author(s):  
Reinhard Alkofer ◽  
Christian S. Fischer ◽  
Hèlios Sanchis-Alepuz
Keyword(s):  
Ground State ◽  
Bound States ◽  
Body Wave ◽  
Form Factors ◽  
Wave Functions ◽  
Electromagnetic Form Factors ◽  
Transition Form ◽  
Electromagnetic Transition ◽  
Three Body ◽  
Gluon Interaction

The covariant Faddeev approach which describes baryons as relativistic three-quark bound states and is based on the Dyson-Schwinger and Bethe-Salpeter equations of QCD is briefly reviewed. All elements, including especially the baryons’ three-body-wave-functions, the quark propagators and the dressed quark-photon vertex, are calculated from a well-established approximation for the quark-gluon interaction. Selected previous results of this approach for the spectrum and elastic electromagnetic form factors of ground-state baryons and resonances are reported. The main focus of this talk is a presentation and discussion of results from a recent investigation of the electromagnetic transition form factors between ground-state octet and decuplet baryons as well as the octet-only Σ0 to Λ transition.

Nucleon electromagnetic form factors from lattice QCD

2004 ◽  
pp. 9-14
Author(s):  
J. D. Ashley ◽  
D. B. Leinweber ◽  
A. W. Thomas ◽  
R. D. Young
Keyword(s):  
Lattice Qcd ◽  
Form Factors ◽  
Electromagnetic Form Factors

scholarly journals Strange nucleon electromagnetic form factors from lattice QCD

2018 ◽  
Vol 97 (9) ◽  
Author(s):  
C. Alexandrou ◽  
M. Constantinou ◽  
K. Hadjiyiannakou ◽  
K. Jansen ◽  
C. Kallidonis ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Form Factors ◽  
Electromagnetic Form Factors

scholarly journals D → Klv semileptonic decay using lattice QCD with HISQ at physical pion masses

2018 ◽  
Vol 175 ◽  
pp. 13027 ◽  
Author(s):  
Bipasha Chakraborty ◽  
Christine Davies ◽  
Jonna Koponen ◽  
G Peter Lepage
Keyword(s):  
Standard Model ◽  
Lattice Qcd ◽  
Semileptonic Decay ◽  
Light Quark ◽  
Form Factors ◽  
New Physics ◽  
Ckm Matrix ◽  
Quark Masses ◽  
The Standard Model ◽  
Fertile Ground

he quark flavor sector of the Standard Model is a fertile ground to look for new physics effects through a unitarity test of the Cabbibo-Kobayashi-Maskawa (CKM) matrix. We present a lattice QCD calculation of the scalar and the vector form factors (over a large q2 region including q2 = 0) associated with the D→ Klv semi-leptonic decay. This calculation will then allow us to determine the central CKM matrix element, Vcs in the Standard Model, by comparing the lattice QCD results for the form factors and the experimental decay rate. This form factor calculation has been performed on the Nf = 2 + 1 + 1 MILC HISQ ensembles with the physical light quark masses.

scholarly journals N-to-ΔElectromagnetic-Transition Form Factors from Lattice QCD

2005 ◽  
Vol 94 (2) ◽  
Author(s):  
C. Alexandrou ◽  
Ph. de Forcrand ◽  
H. Neff ◽  
J. W. Negele ◽  
W. Schroers ◽  
...  
Keyword(s):  
Lattice Qcd ◽  
Form Factors ◽  
Transition Form
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