First observed in the 1960s among a class of particles called mesons, which are made up of a quark–antiquark pair, the violation of "charge-parity (CP)" symmetry has been the subject of intense ...

Discovered in 1995, the top quark is the most massive elementary particle that exists, outweighing even the Higgs boson. Because of its atypical size as compared to other quarks, scientists were ...