Electromagnetic form factors of the proton in the “unphysical” region from the γp → pe+e− reaction

Investigation of the proton factor F1(q2, W2) in the time-like region 4me2 < q2 < 4M2 by measuring the e+e−-asymmetry in the γ(p,p)e+e− reaction is proposed. Selection of “longitudinal” photons (q2 ⪡ q2 ⪡ 4M2) suppresses contributions of F2 and nucleon resonances.