SEMINAR      Friday, January 9th 2004 - h. 15:00  Auditorium B. Touschek     F. Iachello (Yale University)   Structure of the Nucleon Electromagnetic Form Factors Abstract     Recent measurements at the Thomas Jefferson Laboratory of the ratio of electric to magnetic form factors of the proton, GEp /GMp , in the space-like region show dramatic deviations from accepted views of the structure of the proton.     The new data indicate a rather complex structure with at least two components, an intrinsic component with root mean square radius about 0.33 fm and a meson cloud with radius about 0.86 fm.      An analysis of the form factor of the proton and the neutron in terms of basic symmetries, relativistic invariance and isospin invariance, will be presented. This analysis, when extended to the time-like region, shows also dramatic differences from accepted views.     It is concluded that measurements of the form factors of protons and neutrons in the time-like region are of crucial importance for understanding the structure of the nucleon, the basic building block of matter. Experiments are suggested.