1815 - William Prout hypothesizes that all matter is built up from hydrogen, adumbrating the proton; 1838 - Richard Laming hypothesized a subatomic particle carrying electric charge; 1858 - Julius Plücker produced Cathode rays; 1874 - George Johnstone Stoney hypothesizes a minimum unit of electric charge. In 1891, he coins the word electron for it; 1886 - Eugene Goldstein produced Anode rays; 1897 - J. J. Thomson discovered the electron; 1899 - Ernest Rutherford discovered the alpha and beta particles emitted by uranium; 1900 - Paul Villard discovered the Gamma ray in uranium decay. 20th century 1905 - Albert Einstein hypothesized the photon to explain the photoelectric effect. 1911 - Ernest Rutherford discovered the nucleus of an atom; 1919 - Ernest Rutherford discovered the proton; 1928 - Paul Dirac postulated the existence of positrons as a consequence of the Dirac equation; 1930 - Wolfgang Pauli postulated the neutrino to explain the energy spectrum of beta decays; 1932 - James Chadwick discovered the Neutron; 1932 - Carl D. Anderson discovered the Positron; 1935 - Hideki Yukawa predicted the existence of mesons as the carrier particles of the strong nuclear force; 1936 - Carl D. Anderson discovered the muon while he studied cosmic radiation; 1947 - George Dixon Rochester and Clifford Charles Butler discovered the Kaon, the first strange particle; 1947 - Cecil Powell, Cesar Lattes and Giuseppe Occhialini discovered the pion; 1955 - Owen Chamberlain, Emilio Segre, Clyde Wiegand, and Thomas Ypsilantis discovered the Antiproton; 1956 - Clyde Cowan and Frederick Reines discovered the neutrino; 1957 - Bruno Pontecorvo postulated the flavor oscillation; 1962 - Leon M. Lederman, Melvin Schwartz and Jack Steinberger discovered the muon neutrino; 1967 - Bruno Pontecorvo postulated the Neutrino oscillation; 1974 - Burton Richter and Samuel Ting discovered the J/ψ particle; 1977 - Upsilon particle discovered at Fermilab, demonstrating the existence of the bottom quark; 1977 - Martin Lewis Perl discovered the Tau lepton after a series of experiments; 1979 - Gluon observed indirectly in three jet events at DESY; 1983 - Carlo Rubbia and Simon van der Meer discovered the W and Z bosons; 1995 - Top quark discovered at Fermilab; 2000 - Tau neutrino proved distinct from other neutrinos at Fermilab. 2012 - Higgs-Boson-like particle discovered at CERN's Large Hadron Collider (LHC).