Recent direct and indirect experimental evidence, including findings from the ALPHA-g collaboration, demonstrates that antihydrogen experiences gravitational attraction to the Earth rather than repulsion, refuting the hypothesis that antimatter possesses negative gravitational mass.
The claim states that antimatter has positive inertial mass and negative gravitational mass (antigravity). Multiple retrieved papers directly test this hypothesis using antihydrogen and relativistic particles. The ALPHA-g study (Paper 3) and bounds from LEP/Tevatron (Paper 9) directly refute the existence of negative gravitational mass for antimatter, showing it is attracted to Earth. Therefore, the evidence clearly opposes the claim.