2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/172264We 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 polarized beam) in $\bar{p}+{p}\to \ell^++\ell^-$, in view of the availability of future antiproton beams.7 pages 1 table DAPNIA REPORT -04-10, 01/2004High Energy Physics - PhenomenologyNew possibility for further measurements of nucleon form factors at large momentum transfer in time-like region: $\bar{p}+{p}\to \ell^+ +\ell^-$, $\ell=e$ or $μ$text