Strange quark
The first strange particle (a particle containing a strange quark) was discovered in 1947 (kaons), but the existence of the strange quark itself (and that of the up and down quarks) was only postulated in 1964 by Murray Gell-Mann and George Zweig to explain the Eightfold Way classification scheme of hadrons. The first evidence for the existence of quarks came in 1968, in deep inelastic scattering experiments at the Stanford Linear Accelerator Center. These experiments confirmed the existence of up and down quarks, and by extension, strange quarks, as they were required to explain the Eightfold Way.
History of science and technology in Japan
The bottom quark is a product in almost all top quark decays, and is a frequent decay product for the Higgs boson. The bottom quark was theorized in 1973 by physicists Makoto Kobayashi and Toshihide Maskawa to explain CP violation. Toshihide Maskawa and Makoto Kobayashi's 1973 article, "CP Violation in the Renormalizable Theory of Weak Interaction", is the fourth most cited high energy physics paper of all time as of 2010. They discovered the origin of the explicit breaking of CP symmetry in the weak interactions. The Cabibbo–Kobayashi–Maskawa matrix, which defines the mixing parameters between quarks, was the result of this work. Kobayashi and Maskawa were awarded the 2008 Nobel Prize in Physics "for the discovery of the origin of the broken symmetry which predicts the existence of at least three families of quarks in nature."Leo Esaki was awarded the 1973 Nobel Prize in Physics for the discovery of electron tunneling (quantum tunnelling) in the 1950s. The tunnel diode (Esaki diode) was invented in August 1957 by Leo Esaki, Yuriko Kurose and Takashi Suzuki when they were working at Tokyo Tsushin Kogyo, now Sony.