Extraction of proton form factors in the timelike region from unpolarized e+e- --> p pbar events

Abstract

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 typical Born expression, we can extract information on the ratio |G_E/G_M| of the proton electromagnetic form factors in the timelike region within a 5-10% uncertainty. We have explored also non-Born contributions to the cross section by introducing a further component in the angular fit, which is related to two-photon exchange diagrams. We show that these corrections can be identified if larger than 5% of the Born contribution, and if relative phases of the complex form factors do not produce severe cancellations.

arXiv comment10 pages in RevTeX style; 8 figures in eps format

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Cited by in corpus (5)

• Prospects for e+e- physics at Frascati between the phi and the psi
• The fourth dimension of the nucleon structure: spacetime analysis of the timelike electromagnetic proton form factors
• Helicity amplitudes and crossing relations for antiproton proton reactions
• Extraction of proton form factors in the timelike region from single-polarized e+ e- -> \vec p anti-p events
• Soft rescattering in the timelike proton form factor within a spacetime scheme