RAPIDITY GAP EVENTS AND SHADOWING IN DEEP-INELASTIC SCATTERING

We suggest that the ''rapidity gap'' events reported from HERA are essentially the diffraction dissociation channels corresponding to the scaling shadowing seen on nuclei. We stress the interest of checking for virtual photons the old ''inelastic optical theorem'' relation connecting diffraction dissociation of the photon and the total cross section. We explain how it is possible at high q2 to have shadowing, if this relation holds, even though diffractive processes - narrowly defined - become negligible in the total rate.