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We report the calculation of electromagnetic form factors of nucleons within a relativistic three-quark model with Gaussian shape for the nucleon-quark vertex. The allowed region for two adjustable parameters, the range parameter…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. A. Ivanov , M. P. Locher , V. E. Lyubovitskij

A novel method is employed to compute the pion electromagnetic form factor, F_\pi(Q^2), on the entire domain of spacelike momentum transfer using the Dyson-Schwinger equation (DSE) framework in quantum chromodynamics (QCD). The DSE…

Nuclear Theory · Physics 2015-06-16 L. Chang , I. C. Cloet , C. D. Roberts , S. M. Schmidt , P. C. Tandy

The electromagnetic form factors are crucial to our understanding of the proton internal structure, and thus provide a strong constraint of the distributions of the charge and magnetization current within the proton. We adopted the…

High Energy Physics - Phenomenology · Physics 2007-05-23 M Y Hussein

Using our present knowledge on effective hadronic theories, short-distance QCD information, the $1/N_C$ expansion, analyticity and unitarity, we derive an expression for the pion form factor, in terms of $m_\pi, m_K, M_\rho$ and $f_\pi$.…

High Energy Physics - Phenomenology · Physics 2011-05-05 F. Guerrero , A. Pich

I review recently conducted measurements of $\gen$ as well as precision form factor experiments at high momentum transfer that will be performed with the 11 GeV electron beam at Jefferson Lab.

Nuclear Experiment · Physics 2014-11-21 Andrei Semenov

Recent measurements of the ratio of the elastic electromagnetic form factors of the proton, G_Ep/G_Mp, using the polarization transfer technique at Jefferson Lab show that this ratio decreases dramatically with increasing Q^2, in…

High Energy Physics - Experiment · Physics 2009-11-07 E. J. Brash , A. Kozlov , Sh. Li , G. M. Huber

We develop a methodology that enables us to extract accurately the electromagnetic Delta form factors and their momentum dependence. We test our approach in the quenched approximation as a preparation for a study using dynamical fermions.…

High Energy Physics - Lattice · Physics 2008-11-26 Constantia Alexandrou , Tomasz Korzec , Theodoros Leontiou , John W. Negele , Antonios Tsapalis

We investigate the pion and kaon (pi^+, K^+, K^0) electromagnetic form factors in the space-like region: Q^2 ~< 1 GeV, based on the gauged low-energy effective chiral action from the instanton vacuum in the large N_c limit. Explicit flavor…

High Energy Physics - Phenomenology · Physics 2008-11-26 Seung-il Nam , Hyun-Chul Kim

We present nucleon observables - primarily isovector vector form factors - from calculations using 2+1 flavors of Wilson quarks. One ensemble is used for a dedicated high-precision study of excited-state effects using five source-sink…

High Energy Physics - Lattice · Physics 2014-02-05 Jeremy Green , Michael Engelhardt , Stefan Krieg , Stefan Meinel , John Negele , Andrew Pochinsky , Sergey Syritsyn

We use a version of the instant-form relativistic quantum mechanics of composite systems to obtain the gravitational form factors of the pion in a common approach to its electroweak and gravitational properties. In the preceding work…

High Energy Physics - Phenomenology · Physics 2022-09-16 A. F. Krutov , V. E. Troitsky

We use the world data on the pion form factor for space-like kinematics and a technique previously used to extract the proton transverse densities to extract the transverse pion charge density and its uncertainty due the incomplete…

Nuclear Experiment · Physics 2014-09-18 Marco Carmignotto , Tanja Horn , Gerald A. Miller

We present results for the isovector axial, induced pseudoscalar, electric, and magnetic form factors of the nucleon. The calculations were done using $2+1+1$-flavor HISQ ensembles generated by the MILC collaboration with lattice spacings…

High Energy Physics - Lattice · Physics 2018-04-18 Yong-Chull Jang , Tanmoy Bhattacharya , Rajan Gupta , Huey-Wen Lin , Boram Yoon

This talk presents issues pertaining to the quark structure of the pion within QCD, both from the theoretical and from the experimental point of view. We review and discuss the pion-photon transition form factor and the pion's…

High Energy Physics - Phenomenology · Physics 2008-11-07 N. G. Stefanis

We compute the electromagnetic charged kaon form factor in the time-like region by employing a Poincar\'e covariant formalism of the Bethe-Salpeter equation to study quark-antiquark bound states in conjunction with the Schwinger-Dyson…

High Energy Physics - Phenomenology · Physics 2023-02-01 A. S. Miramontes , Adnan Bashir

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

The present contribution continues and extends foregoing work on the calculation of electroweak form factors of hadrons using the point-form of relativistic quantum mechanics. Here we are particularly interested in studying pionic effects…

High Energy Physics - Phenomenology · Physics 2015-10-20 D. Kupelwieser , W. Schweiger

We discuss the soft contribution to the elastic pion form factor with the mass evolution from current to constituent quark being taken into account in a light-front quark model(LFQM).

High Energy Physics - Phenomenology · Physics 2009-11-07 Ho-Meoyng Choi , L. S. Kisslinger , Chueng-Ryong Ji

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 ratio of the proton form factors, GEp/GMp, has been measured from Q2 of 0.5 GeV2 to 8.5 GeV2, at the Jefferson Laboratory, using the polarization transfer method. This ratio is extracted directly from the measured ratio of the…

Nuclear Experiment · Physics 2015-06-19 Vina Punjabi , Charles F. Perdrisat

Recent measurement of the $\gamma\gamma^\ast$ form factor of the neutral pion in the high $Q^2$ region disagrees with {\em a priori} predictions of QCD-based calculations. We comment on existing explanations, and analyze a possibility that…

High Energy Physics - Phenomenology · Physics 2012-03-15 David McKeen , Maxim Pospelov , J. Michael Roney
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