Particle Physics Time line
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Year |
Experiment |
Theory |
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1927 |
decay discovered |
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1928 |
Paul Dirac: Wave equation for electron |
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1930 |
Wolfgang Pauli suggests existence of neutrino |
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1931 |
Positron discovered |
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1931 |
Paul Dirac realises that positrons are part of his equation |
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1931 |
Chadwick discovers neutron |
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1933/4 |
Fermi introduces theory for decay |
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1933/4 |
Hideki Yukawa discusses nuclear binding in terms of pions |
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1937 |
discovered in cosmic rays |
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1938 |
Baryon number conservation |
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1946 |
is not Yukawa’s particle |
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1947 |
discovered in cosmic rays |
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1946-50 |
Tomonaga, Schwinger and Feynman develop QED |
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1948 |
First artificial ’s |
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1949 |
discovered |
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1950 |
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1951 |
”V-particles” and |
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1952 |
: excited state of nucleon |
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1954 |
Yang and Mills: Gauge theories |
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1956 |
Lee and Yang: Weak force might break parity! |
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1956 |
CS Wu and Ambler: Yes it does. |
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1961 |
Eightfold way as organising principle |
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1962 |
and |
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1964 |
Quarks (Gell-man and Zweig) |
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1964 |
Fourth quark suggested ( ) |
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1965 |
Colour charge all particles are colour neutral! |
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1967 |
Glashow-Salam-Weinberg unification of electromagnetic and weak interactions. Predict Higgs boson. |
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1968-69 |
DIS at SLAC constituents of proton seen! |
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1973 |
QCD as the theory of coloured interactions. Gluons. |
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1973 |
Asymptotic freedom |
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1974 |
( ) meson |
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1976 |
meson ( ) confirms theory. |
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1976 |
lepton! |
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1977 |
b (bottom quark). Where is top? |
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1978 |
Parity violating neutral weak interaction seen |
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1979 |
Gluon signature at PETRA |
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1983 |
and seen at CERN |
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1989 |
SLAC suggests only three generations of (light!) neutrinos |
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1995 |
t (top) at 175 GeV mass |
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1997 |
New physics at HERA (200 GeV) |
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