Related papers: Two-Photon Exchange Contribution to Proton Form Fa…
We compute the two photon exchange contributions to elastic scattering of polarized electrons from target protons. We use a nonlocal field theory formalism for this calculation. The formalism maintains gauge invariance and provides a…
Corrections of two-photon exchange to proton and neutron electromagnetic form factors are employed to study the effect of two-photon exchange on the deuteron electromagnetic form factors. Numerical results of the effect are given. It is…
We estimate the two-photon exchange corrections to both proton and neutron electromagnetic physical observables in a relativistic light cone quark model. At a fixed momentum transfer the corrections are found to be small in magnitudes, but…
We have performed numerical simulations of the unpolarized e+e- --> p pbar process in kinematic conditions under discussion for a possible upgrade of the existing DAFNE facility. By fitting the cross section angular distribution with a…
We extract the two-photon exchange (TPE) contributions to electron--proton elastic scattering using two parametrizations and compare the results to different phenomenological extractions and direct calculations of the TPE effects. We find…
We investigate the two-photon corrections to the process $p\bar{p} \to e^+e^-$ at large momentum transfer, aimed to access the time-like nucleon form factors. We estimate the two-photon corrections using a hard rescattering mechanism, which…
The two-photon-exchange (TPE) effects in the process $e^+e^- \rightarrow \pi^+\pi^-$ at large momentum transfer are discussed within the perturbative QCD (pQCD). The contributions from the twist-2 and twist-3 distribution amplitudes (DAs)…
The resonances ($\eta_c,\chi_{c0,c2}$) contribution to two-photon exchange (TPE) effects in $e^+ e^- \leftrightarrow p \bar{p}$ is calculated in a simple hadronic model. The calculation shows the TPE contributions by resonance $\chi_{c2}$,…
We compute the corrections from two-photon and photon-Z exchange in parity-violating elastic electron-proton scattering, used to extract the strange form factors of the proton. We use a hadronic formalism that successfully reconciled the…
Polarization observables for the reaction $\bar p+p\to e^++e^-$ are given in terms of three independent complex amplitudes, in presence of two photon exchange. General expressions for the differential cross section and the polarization…
The presence of two photon exchange in $ep$ elastic scattering and in the crossed processes ($\bar p +p\leftrightarrow \ell^+ +\ell^-$, $\ell=e$ or $\mu$) is discussed in terms of three complex amplitudes which are functions of two…
Recent theoretical developments in the studies of two-photon exchange effects in elastic electron-proton scattering are reviewed. Two-photon exchange mechanism is considered a likely source of discrepancy between polarized and unpolarized…
We show that measurements of the proton's polarization in electron-positron annihilation to a proton-antiproton pair $e^+ e^- \to p \bar p$ strongly discriminate between the analytic forms of models which fit the proton form factors in the…
The aim of this work is to give a pedagogical derivation of polarization observables for the annihilation reaction $e^+ + e^- \to N+ \bar N$. The reaction mechanism is one photon + two photon exchange, the last is described by axial…
We evaluate the two-photon exchange correction to the elastic electron-proton scattering cross section within a dispersive framework. Besides the elastic contribution, we account for all $\pi N$ intermediate state contributions using the…
Motivated by experimental data at large momentum transfer we update the analysis of the two-photon exchange effect in the electron-nucleon scattering using the effective field theory formalism. Our approach is suitable for describing the…
We estimate the two-photon exchange contribution to elastic electron-proton scattering at large momentum transfer through the scattering off a parton in the proton. We relate the process on the nucleon to the generalized parton…
The discussion on the asymptotical behaviour of the form factors in the space-like and time-like regions have been corrected and clarified. Fig.3 has been replaced by an improved analysis of the data.
We use the world's data on elastic electron--proton scattering and calculations of two-photon exchange effects to extract corrected values of the proton's electric and magnetic form factors over the full Q^2 range of the existing data. Our…
We have performed numerical simulations of the single-polarized e+ e- --> \vec p anti p process in kinematic conditions under discussion for a possible upgrade of the existing DAFNE facility. By fitting the cross section and spin asymmetry…