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Charge symmetry breaking contributions to the proton's neutral weak form factors must be understood in order for future measurements of parity violating electron-proton scattering to be definitively interpreted as evidence of proton…

Nuclear Theory · Physics 2014-12-17 Michael Wagman , Gerald A. Miller

In experiment on the study of the quasielastic pion-proton scattering at large momentum transfer on nuclei the proton Fermi-momentum distributions have been analysed in plane-wave approximation for light nuclei $^6$Li, $^7$Li and $^{12}$C.…

The ratio of the squares of the electric and magnetic proton form factors is shown to be proportional to the ratio of the cross sections for the elastic scattering of an unpolarized electron on a partially polarized proton with and without…

High Energy Physics - Phenomenology · Physics 2009-03-12 M. V. Galynskii , E. A. Kuraev , Yu. M. Bystritskiy

Using a continuum approach to the hadron bound-state problem, we calculate $\gamma^\ast \gamma \to \eta, \eta^\prime$ transition form factors on the entire domain of spacelike momenta, for comparison with existing experiments and in…

Dispersion relations provide a powerful tool to analyse the electromagnetic form factors of the nucleon for all momentum transfers. Constraints from meson-nucleon scattering data, unitarity, and perturbative QCD can be included in a…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. A. Belushkin , H. -W. Hammer , U. -G. Meißner

The proton and neutron make up over 99.9\% of visible matter in the universe. The internal structure of protons, governed by ElectroMagnetic Form Factors (EMFFs), has been probed in both space-like (SL) and time-like (TL) regions. The…

High Energy Physics - Experiment · Physics 2026-01-12 Lei Xia

We have measured the cross section $\sigma(e^+e^-\to\pi^+\pi^-\gamma(\gamma))$ at DA$\Phi$NE, the Frascati \phi-factory, using events with initial state radiation photons emitted at small angle and inclusive of final state radiation. We…

High Energy Physics - Experiment · Physics 2012-08-27 KLOE Collaboration

The cross section of the $ep \to e' p' \gamma$ reaction has been measured at $Q^2 = 0.33$ (GeV/c)$^2$. The experiment was performed using the electron beam of the MAMI accelerator and the standard detector setup of the A1 Collaboration. The…

There has been considerable progress in the study of the electromagnetic form factors of baryons in the timelike region, through electron-positron scattering reactions ($e^+ e^- \to B \bar B$), in the last two decades. Timelike experiments…

High Energy Physics - Phenomenology · Physics 2026-05-19 G. Ramalho , M. T. Peña , K. Tsushima , Myung-Ki Cheoun

We report on a measurement of the parity violating asymmetry in the elastic scattering of polarized electrons off unpolarized protons with the A4 apparatus at MAMI in Mainz at a four momentum transfer value of $Q^2$ = \Qsquare (GeV/c)$^2$…

Using a three-dimensional formalism that includes relativistic kinematics, the effects of negative-energy states, approximate boosts of the two-body system, and current conservation, we calculate the electromagnetic form factors of the…

Nuclear Theory · Physics 2009-04-17 D. R. Phillips , S. J. Wallace , N. K. Devine

The measurements of psi(2S) -> omega pi0 and psi(2S) -> pi+ pi- in e+e- experiments are examined. It is found that the non-resonance virtual photon annihilation gives large contributions to the observed cross sections of these two…

High Energy Physics - Phenomenology · Physics 2016-09-06 P. Wang , X. H. Mo , C. Z. Yuan

The three-dimensional structure of nucleons (protons and neutrons) is embedded in so-called generalized parton distributions, which are accessible from deeply virtual Compton scattering. In this process, a high energy electron is scattered…

Interpreting measurements requires a physical theory, but the theory's accuracy may vary across the experimental domain. To optimize experimental design, and so to ensure that the substantial resources necessary for modern experiments are…

The nucleon electromagnetic form factors G_E and G_M are complex quantities in the time-like region. The absolute values can be determined by measuring the angular distribution of the nucleons in e^+ e^- --> N N-bar. The complex phase can…

High Energy Physics - Experiment · Physics 2007-05-23 Stephen Rock

The BESIII experiment, based on the BEPCII collider at IHEP in Beijing, China, is capable of measuring nucleon form factors with unprecedented precision. We report recent results achieved by the BESIII collaboration concerning the nucleon…

High Energy Physics - Experiment · Physics 2022-02-01 Alessio Mangoni

We perform a global analysis of all recent experimental data from elastic parity-violating electron scattering at low $Q^2$. The values of the electric and magnetic strange form factors of the nucleon are determined at $Q^2 = 0.1$ GeV/$c^2$…

Nuclear Experiment · Physics 2008-11-26 Jianglai Liu , Robert D. McKeown , Michael J. Ramsey-Musolf

The elastic and $\gamma \to \pi$ transition form factors of the pion along with its usual static observables are calculated within a light-front field approach to the constituent quark model. The focus of this exercise in a simple model is…

Nuclear Theory · Physics 2015-06-18 J. P. B. C. de Melo , B. El-Bennich , T. Frederico

The strange quark contributions to the electromagnetic form factors of the proton are ideal quantities to study the role of hidden flavor in the properties of the proton. This has motivated intense experimental measurements of these form…

Nuclear Theory · Physics 2020-08-05 Ali Alkathiri , Ross D. Young , James M. Zanotti

We perform a global analysis of the experimental data of the electromagnetic nucleon form factors, in space-like and time-like regions. We give the expressions of the observables in annihilation processes, such as $p+\bar{p}\to \ell^+…

Nuclear Theory · Physics 2014-11-18 Egle Tomasi-Gustafsson , F. Lacroix , C. Duterte , G. I. Gakh