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Predictions for the electromagnetic form factors of the Lambda$, Sigma and Xi hyperons are presented. The numerical calculations are performed within the framework of the fully relativistic constituent-quark model developed by the Bonn…

Nuclear Theory · Physics 2009-11-10 T. Van Cauteren , D. Merten , T. Corthals , S. Janssen , B. Metsch , H. -R. Petry , J. Ryckebusch

The electromagnetic form factors of the proton and the neutron in the timelike region are investigated. Electron-positron annihilation into antinucleon-nucleon ($\bar NN$) pairs is treated in distorted wave Born approximation, including the…

Nuclear Theory · Physics 2023-12-06 Qin-He Yang , Ling-Yun Dai , Di Guo , Johann Haidenbauer , Xian-Wei Kang , Ulf-G. Meißner

QCD gives definite predictions for hadron electromagnetic form factors in space-like and time-like momentum transfer regions, such as the quark counting rules, the hypothesis of hadron helicity conservation, and the relations between…

Nuclear Theory · Physics 2007-05-23 Egle Tomasi-Gustafsson , Michail P. Rekalo

The pion mass dependence of hyperon electromagnetic properties is determined using two-flavor heavy baryon chiral perturbation theory. Specifically we compute chiral corrections to the charge radii, magnetic moments, and magnetic radii of…

Nuclear Theory · Physics 2010-04-06 Fu-Jiun Jiang , Brian C. Tiburzi

The reaction $e^+e^- \to \bar \Lambda \Lambda$ is investigated for energies close to the threshold. Specific emphasis is put on the role played by the interaction in the final $\bar \Lambda \Lambda$ system which is taken into account…

Nuclear Theory · Physics 2016-10-12 J. Haidenbauer , U. -G. Meißner

We compute the $\Lambda_b \to \Lambda$ transition form factors using light-cone sum rules based on $\Lambda$-baryon distribution amplitudes, including contributions up to twist--6. The analysis is performed for pseudoscalar, vector, and…

High Energy Physics - Phenomenology · Physics 2026-01-07 F. Mahmoudi , D. Mishra

We investigate the ten independent local form-factors relevant to the $b$-baryon decay $\Lambda_b \to \Lambda \ell^+\ell^-$, combining information of lattice QCD and dispersive bounds. We propose a novel parametrization of the form factors…

High Energy Physics - Phenomenology · Physics 2023-11-27 Thomas Blake , Stefan Meinel , Muslem Rahimi , Danny van Dyk

The nucleon isovector electromagnetic form factors are calculated up to next-to-next-to-leading order by combining relativistic chiral perturbation theory (ChPT) of pion, nucleon, and $\Delta$(1232) with dispersion theory. We specifically…

High Energy Physics - Phenomenology · Physics 2023-12-18 Fernando Alvarado , Di An , Luis Alvarez-Ruso , Stefan Leupold

A review of recent precision measurements of the electromagnetic form factors of the mesons, pion and kaon, and the hyperons, $\Lambda^0$, $\Sigma^0$, $\Sigma^+$, $\Xi^-$, $\Xi^0$, $\Omega^-$, at large timelike momentum transfers is…

High Energy Physics - Experiment · Physics 2015-06-18 Kamal K. Seth

I review the results of a recent dispersion--theoretical analysis of the nucleon electromagnetic form factors and comment on the strangeness form factors. The need for a better data basis at low, intermediate and large momentum transfer is…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ulf-G. Meißner

Recently, the BESIII experiment renewed the interest on baryon form factors by measuring the modulus and phase of the ratio $G_E^\Lambda/G_M^\Lambda$ between the electric and the magnetic $\Lambda$ form factors with unprecedented accuracy.…

High Energy Physics - Phenomenology · Physics 2022-01-05 Alessio Mangoni , Simone Pacetti , Egle Tomasi-Gustafsson

We study the nucleon, Sigma and cascade octet baryon electromagnetic form factors and the effects of SU(3) flavor symmetry breaking from 2+1-flavor lattice calculations. We find that electric and magnetic radii are similar; the maximum…

High Energy Physics - Lattice · Physics 2014-11-18 Huey-Wen Lin , Kostas Orginos

Some form factors of ground-state hadrons with spin might show a zero crossing at spacelike momenta of electron-hadron scattering. In the timelike region of hadron-antihadron production by electron-positron collisions the form factors…

High Energy Physics - Phenomenology · Physics 2021-12-24 Stefan Leupold

Data on electromagnetic form factors of proton, neutron, and $\Lambda$ from annihilation and scattering reactions are collected and interpreted in the frame of a generalized picture of the internal structure of baryons which holds in…

Nuclear Theory · Physics 2022-05-20 Egle Tomasi-Gustafsson , Simone Pacetti

We apply the methods of Chiral Perturbation Theory to the analysis of the first moments of the Generalized Parton Distributions in a Nucleon, usually known as generalized form factors. These quantities are currently also under investigation…

High Energy Physics - Lattice · Physics 2009-04-14 Marina Dorati , Tobias A. Gail , Thomas R. Hemmert

The electromagnetic form factors $G_{\rm E}$ and $G_{\rm M}$ of the proton and neutron in the timelike region are extracted in a study of the processes $e^+ e^-\to \bar{p}p$ and $e^+ e^-\to \bar{n}n$. The reaction amplitude is evaluated…

Nuclear Theory · Physics 2024-04-22 Qin-He Yang , Di Guo , Ming-Yan Li , Ling-Yun Dai , Johann Haidenbauer , Ulf-G. Meißner

We present a calculation of the electric and magnetic form factors of ground-state octet and decuplet baryons including strange quarks. We work with a combination of Dyson-Schwinger equations for the quark propagator and covariant…

High Energy Physics - Phenomenology · Physics 2016-03-03 Helios Sanchis-Alepuz , Christian S. Fischer

We review the status of baryon form factors with a special focus on the nucleon electromagnetic form factors which are known best. First, we give an introduction into the dispersive analyses and emphasize the role of unitarity and…

High Energy Physics - Phenomenology · Physics 2024-12-23 Yong-Hui Lin , Hans-Werner Hammer , Ulf-G. Meißner

A model is developed for electromagnetic form factors of the charged and neutral K-mesons. The formalism is based on ChPT Lagrangians with vector mesons. The form factors, calculated without fitting parameters, are in a good agreement with…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. A. Ivashyn , A. Yu. Korchin

The pion electromagnetic form factor and two-pion production in electron-positron collisions are simultaneously fitted by a vector dominance model evolving to perturbative QCD at large momentum transfer. This model was previously successful…

High Energy Physics - Phenomenology · Physics 2016-09-14 Earle L. Lomon , Simone Pacetti