or high-energy physics
Study of the fundamental subatomic particles , including both matter (and antimatter ) and the carrier particles of the fundamental interactions as described by quantum field theory .
Particle physics is concerned with structure and forces at this level of existence and below. Fundamental particles possess properties such as electric charge , spin , mass , magnetism , and other complex characteristics, but are regarded as pointlike. All theories in particle physics involve quantum mechanics , in which symmetry is of primary importance. See also electroweak theory , lepton , meson , quantum chromodynamics , quark .