Are there any experimantal evidences which imply that antimatter interacts gravitationally in exactly the same way as matter. I found one argument in "Feynamn lectures on gravitation": Let's consider correction to binding energy of an electron in a atom coming from vacuum polarization. Since this correction involves pairs of particles and antiparticles if antimater gravitational interaction was different then matter interaction then the ratio of gravitational to inertial mass of different substances would be slightly different. Since we don't meassure any differences the matter and antimatter interacts gravitationally in the same way. I consider this type of argumentation as vague. I don't know whether we can treat virtual particles as real (the paris are in this case virtual). Are there any direct evidences of gravitational interaction of antimatter.