noun
antiproton
Technical term in physics for the antiparticle of a proton.
反陽子は陽子と同じ質量を持つが、負の電荷を持つ。
An antiproton has the same mass as a proton but carries a negative charge.
反粒子 is the general term for antiparticle; 反陽子 is a specific type.
Compound of 反 (anti-) and 陽子 (proton).