noun
antiparticle
Physics term for a particle with the same mass but opposite charge and other quantum numbers as a corresponding particle.
陽電子は電子の反粒子である。
A positron is the antiparticle of an electron.
反粒子と粒子が衝突すると対消滅を起こす。
When an antiparticle and a particle collide, they annihilate each other.
反物質 is 'antimatter', the substance composed of antiparticles.
Compound of 反 (anti-) and 粒子 (particle), a direct translation of the English 'antiparticle'.