相关论文: On the Proton Form Factors in the Time-Like Region
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 Fig.3 has been replaced by an improved analysis of the data.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 compare the existing data about electromagnetic form factors of the proton in the time-like region of momentum transfer (up to $q^2\simeq$ 14 (GeV/c)$^2$), with the corresponding data in the space-like region. From the constrains given…
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…
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…
The data on the proton form factors in the time-like region from the BaBar, BESIII and CMD-3 Collaborations are examined to have coherent pieces of information on the proton structure. Oscillations in the annihilation cross section,…
The reactions ppbar -> e+e- and e+e- -> ppbar are analyzed in the near-threshold region. Specific emphasis is put on the role played by the interaction in the initial- or final antinucleon-nucleon state which is taken into account…
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…
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…
We study the asymptotic behavior of the ratio of Pauli and Dirac electromagnetic nucleon form factors, $F_2/F_1$, in time-like region for different parametrizations built for the space-like region. We investigate how fast the ratio…
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…
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^+…
Analyticity of nucleon form factors allows to derive sum rules which, using space-like and time-like data as input, can give unique information about behaviors in energy regions not experimentally accessible. Taking advantage from new…
The electro-magnetic form factors of the proton are calculated in a chiral soliton model with relativistic corrections. The magnetic form factor $G_M$ is shown to agree well with the new SLAC data for spacelike $Q^2$ up to 30 (GeV/c)$^2$ if…
For over 100 years, scientists have investigated the properties of the proton, which is one of the most abundant components of visible matter in the universe. Nevertheless, researchers do not fully understand many details about its internal…
We briefly summarize the status with electromagnetic nucleon form factors, and give in this framework, arguments to study the angular dependence of the differential cross section and single-spin polarization phenomena (polarized target or…
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…
The problem of determining the pion electromagnetic formfactor $F(q^2)$ in the space-like region from the value of its modulus in the time-like region is solved by the formfactor analyticity. If $F(q^2)$has no zeroes in the complex plane…
We update a recent dispersion--theoretical fit to the nucleon electromagnetic form factors by including the existing data in the time--like region. We show that while the time--like data for the proton can be described consistently with the…
In the last few years there has been considerable progress in the study of the electromagnetic form factors of baryons in the timelike region, through electron-positron scattering, with increasing squared transfer momentum $q^2$. The…
The difference between the timelike and spacelike meson form factors is analysed in the framework of perturbative QCD with Sudakov effects included. It is found that integrable singularities appear but that the asymptotic behavior is the…