antiparticle
concept that pairs of particles exist that have equal mass, but opposite sign for properties such as charge, lepton and baryon number
en-GB/æntiːpɑːtɪkl/
en-US/ˈæntiˌpɑɹtɪkəl/
concept that pairs of particles exist that have equal mass, but opposite sign for properties such as charge, lepton and baryon number