No abstract available

[en] The results of experiment PS170 performed at LEAR, at CERN, are presented here. The experiment has determined the values of the proton electromagnetic form factor for s ranging from threshold up to 4.2 GeV². The precise measurements performed show the s dependence near threshold not in agreement with the models describing the results of the previous experiments. The authors have also measured the angular distribution of the e⁺e^- pairs at the different energies. The results are compatible with the |G_E| = |G_M| hypothesis. 6 refs., 2 figs., 1 tab

[en] The electric and magnetic form factors for the nucleon and the N-Δ transition are computed in the semiclassical approximation to the Skyrme model and compared with phenomenological dipole parametrizations. A model-independent relation between the magnetic form factors is obtained. The transverse electric transition form factor is identically zero in this approximation, while the longitudinal form factor is nonzero

[en] A Comment on the Letter by J. C. Bernauer et al., Phys. Rev. Lett. 105, 242001 (2010). The authors of the Letter offer a Reply.

No abstract available

[en] The theory of the pion electromagnetic form factor (space-time extension of π mesons, electromagnetic mean squared radius, form factor and strong interactions) is presented and pion electroproduction (virtual photoproduction cross sections, models using dispersion relations, Kessler and Cochard graphic model) is studied. The relation between the pion electromagnetic form factor and electroproduction is then analyzed

[en] On the example of the electromagnetic structure of the pion we illustrate the interplay between theory, experiment, and mathematics in phenomenology. (author)

[en] The electromagnetic properties of a relativistic constituent-quark model of light nonstrange and strange mesons are investigated within the framework of light-front Hamiltonian dynamics. The authors demonstrate that the Poincare invariant quark model of the pion and kaon can give charge form factors in agreement with all available data. The relativistic features of the model are essential for the result. The radial confinement scale is much smaller than the charge radius due to the sizable effect from the spin-orbit coupling in the meson system

[en] In this paper we calculate the next-to-leading-order (NLO) corrections to ρ-meson electromagnetic form factors by employing the $k_T$ factorization approach. We find that the NLO correction to $F_i(Q^2)(i=LT,TL)$ is around 30% of the leading-order (LO) contribution in the region $Q^2>2{\text{GeV}}^2$. The NLO correction to $F_{LL}(Q^2)$ is close to 20% of the LO one in the region $Q^2>3{\text{GeV}}^2$. The NLO radiative corrections to the electric, magnetic, and quadruple form factors $F_j(Q^2)(j=1,2,3)$ are sizeable in magnitude and agree with those from other approaches.

[en] The author will discuss recent progress in the determination and understanding of the electromagnetic form factors of the A=2,3,4 systems. New data and analyses have allowed one to determine the form factor to significantly larger momentum transfer. From a comparison of the separated isoscalar and isovector, charge and magnetic form factors one can better disentangle the contributions of one-body currents and mesonic degrees of freedom