Sm. Bilenky et al., THE PROCESS (P)OVER-BAR-P-]E-E-FACTORS IN TIME-LIKE REGION( WITH POLARIZED INITIAL PARTICLES AND PROTON FORM), Zeitschrift fur Physik. C, Particles and fields, 59(3), 1993, pp. 475-480
The process ppBAR --> e- e+ is considered in the general case of polar
ized initial particles. A relation between the difference of the phase
s of the electromagnetic form factors G(M) and G(E) in the time-like r
egion and measurable asymmetries is derived. It is shown that the modu
li of the form factors can be determined from measurements of the tota
l unpolarized cross section and of the integral asymmetry for longitud
inally polarized (or transversely polarized) pBAR and p. The behaviour
of the proton form factors at high q2 in the time-like region is also
discussed. From the Phragmen-Lindelof's theorem it follows that the a
symptotical behaviour of the form factors in the space-like and time-l
ike regions must be the same. An analysis of experimental data in both
regions based on perturbative QCD is presented.