#antiproton

• Antiproton — The antiparticle of the proton, possessing identical mass and spin but an opposite, negative electric charge. Experimentally discovered in 1955, the antiproton is a stable composite particle belonging to the hadron class, composed of three antiquarks (two up antiquarks and one down antiquark), whose direct interaction with ordinary matter leads to mutual annihilation, releasing massive energy in the form of gamma rays.
• Antisubstance — A hypothetical or experimental form of matter composed entirely of antiparticles (such as antiprotons, antineutrons, and positrons), representing the structural inverse equivalent of ordinary matter. Upon direct contact between a substance and an antisubstance, the physical process of total annihilation occurs, instantly converting the entire mass of both entities into pure energy in the form of high-intensity gamma rays.