Quarks:
Up Quark:
Mass: 2.4 MeV
Charge: +2/3
Spin: 1/2
Status: Predicted in 1964 by Murray Gell-Mann and George Zweig, discovered in 1969 at SLAC National Accelerator Laboratory
Antiparticle: Antiproton containing two up antiquarks theorized in 1933 by Paul Dirac, discovered in 1955 by Emilio Segrè and Owen Chamberlain
Down Quark:
Mass: 4.8 MeV
Charge: -1/3
Spin: 1/2
Status: Predicted in 1964 by Murray Gell-Mann and George Zweig, discovered in 1969 at SLAC
Antiparticle: Antiproton containing down antiquark theorized in 1933 by Paul Dirac, discovered in 1955 by Emilio Segrè and Owen Chamberlain
Charm Quark:
Mass: 1.27 GeV
Charge: +2/3
Spin: 1/2
Status: Predicted in 1964 by James Bjorken and Sheldon Lee Glashow, existence demonstrated by discovery of J/ψ meson in 1974 by Burton Richter and Samuel Ting
Strange Quark:
Mass: 104 MeV
Charge: -1/3
Spin: 1/2
Status: Predicted in 1964 by Murray Gell-Mann and George Zweig, discovered in 1969 at SLAC
Top Quark:
Mass: 171.2 GeV
Charge: +2/3
Spin: 1/2
Status: Predicted in 1973 by Makoto Kobayashi and Toshihide Maskawa, discovered in 1995 at Fermilab
Bottom Quark:
Mass: 4.2 GeV
Charge: -1/3
Spin: 1/2
Status: Predicted in 1973 by Makoto Kobayashi and Toshihide Maskawa, existence demonstrated through discovery of upsilon meson in 1977 at Fermilab
Leptons:
Electron:
Mass: .511 MeV
Charge: -1
Spin: 1/2
Lifetime: Greater than 4.6 * 10^26 years
Status: Discovered in 1897 by J.J. Thomson
Antiparticle: Positron theorized in 1927 by Paul Dirac, discovered in 1932 by Carl D. Anderson
Electron Neutrino:
Mass: Less than 2.2 eV
Charge: 0
Spin: 1/2
Status: Theorized in 1931 by Wolfgang Pauli, discovered in 1956 by Frederick Reines and Clyde Cowan
Muon:
Mass: 105.7 MeV
Charge: -1
Spin: 1/2
Lifetime: 2.2 * 10^-6 seconds
Status: Discovered in 1937 by Seth Neddermeyer, Carl D. Anderson, J.C. Street, and E.C. Stevenson, although mistaken for pion until 1947
Muon Neutrino:
Mass: Less than 0.17 MeV
Charge: 0
Spin: 1/2
Status: Shown to be distinct from electron neutrino in 1962 by Leon Lederman
Tau:
Mass: 1.777 GeV
Charge: -1
Spin: 1/2
Lifetime: 2.9 * 10^-13 seconds
Status: Discovered in 1975 by Martin Perl
Tau Neutrino:
Mass: Less than 15.5 MeV
Charge: 0
Spin: 1/2
Status: Observed indirectly in 2000 at Fermilab
Bosons
Photon:
Mass: 0
Charge: 0
Spin: 1
Carries: Electromagnetic force
Status: Discovered in 1895 by Wilhelm Röntgen in the form of X-ray photons
Gluon:
Mass: 0
Charge: 0
Spin: 1
Carries: Strong nuclear force
Status: Observed indirectly in 1979 at DESY, the German Electron Synchrotron
Z Boson:
Mass: 91.2 GeV
Charge: 0
Spin: 1
Lifetime: 10^-25 seconds
Carries: Weak nuclear force
Status: Predicted by Sheldon Glashow, Abdus Salam, and Steven Weinberg, discovered in 1983 by Carlo Rubbia, Simon van der Meer, and CERN, the European Organization for Nuclear Research
W Boson:
Mass: 80.4 GeV
Charge: Either +1 or -1
Spin: 1
Lifetime: 10^-25 seconds
Carries: Weak nuclear force
Status: Predicted by Sheldon Glashow, Abdus Salam, and Steven Weinberg, discovered in 1983 by Carlo Rubbia, Simon van der Meer, and CERN
And the two most important composite particles:
Proton:
Components: Two up quarks and one down quark
Mass: 938.272 MeV
Charge: 1 (2/3 + 2/3 – 1/3)
Spin: 1/2
Lifetime: Greater than 2.1 * 10^29 years
Status: Discovered in 1919 by Ernest Rutherford
Neutron:
Components: One up quark and two down quarks
Mass: 939.565 MeV
Charge: 0 (2/3 – 1/3 – 1/3)
Spin: 1/2
Lifetime: 885.7 seconds
Status: Theorized in 1920 by Ernest Rutherford, discovered in 1932 by James Chadwick
Notes:
All antiparticles have opposite charge and identical mass, spin, and lifetime. Specific antiparticles only listed when their discoveries were significant to development of Standard Model.
All masses are given in electron volts.
Quarks do not have lifetimes listed because they are always found combined in nature. The neutrino and gluon lifetimes are not currently well understood. The photon is stable and does not decay.
