Toshihide Maskawa and Makoto Kobayashi investigated how CP violation could fit within a renormalizable theory of the weak interaction. A complex quark mixing matrix is not enough by itself: phases removable by redefining quark fields have no physical effect. With three fermion generations, a physical complex phase can remain in the Cabibbo-Kobayashi-Maskawa matrix. Their 1973 analysis connected an observed symmetry failure with the possible number and organization of quarks.[ref]
CP-Violation in the Renormalizable Theory of Weak Interaction by Makoto Kobayashi and Toshihide Maskawa. 1973, six-quark scheme and phases of the three-by-three unitary mixing matrix
A physicist working on quark mixing.[ref]
Professional profile of Toshihide Maskawa. Independent professional identity
Portrait of Toshihide Maskawa
. 日本学士院ホームページ (Japan Academy website). CC BY 4.0, via Wikimedia Commons. Source. Articles by others on the same topic
Toshihide Maskawa is a prominent Japanese theoretical physicist known for his significant contributions to the field of particle physics. He was born on June 7, 1940. Maskawa is best known for his work on the unification of the weak interaction and quantum chromodynamics and for the development of the theory of the oscillation of quarks, which helped to explain the phenomenon of CP violation (charge-parity violation) in particle physics.