Editing Timeline of atomic and subatomic physics

{{Short description|none}} <!-- This short description is INTENTIONALLY "none" - please see WP:SDNONE before you consider changing it! -->
{{Use dmy dates|date=August 2019}}
A [[timeline]] of [[atomic physics|atomic]] and [[subatomic particle|subatomic]] physics, including [[particle physics]].

==Antiquity==

* 6th - 2nd Century BCE  [[Kanada (philosopher)]] proposes that  ''anu'' is an indestructible particle of matter, an "atom"; anu is an abstraction and not observable.<ref name="Roopa Narayan">{{cite book|url=http://www.ece.lsu.edu/kak/roopa51.pdf|title=Space, Time and Anu in Vaisheshika|last=Narayan|first=Rupa|publisher=Louisiana State University, Baton Rouge, USA|year=2013}}</ref>

* 430 BCE<ref name="Teresi">{{cite book|url=https://books.google.com/books?id=pheL_ubbXD0C&pg=PA214|title=Lost Discoveries: The Ancient Roots of Modern Science|last=Teresi|first=Dick|publisher=Simon and Schuster|year=2010|isbn=978-1-4391-2860-2|pages=213–214}}</ref> [[Democritus]] speculates about fundamental indivisible particles—calls them "[[atom]]s"

==The beginning of chemistry==
* 1766 [[Henry Cavendish]] discovers and studies [[hydrogen]]
* 1778 [[Carl Scheele]] and [[Antoine Lavoisier]] discover that [[Earth's atmosphere|air]] is composed mostly of [[nitrogen]] and [[oxygen]]
* 1781 [[Joseph Priestley]] creates water by igniting hydrogen and oxygen
* 1800 [[William Nicholson (chemist)|William Nicholson]] and [[Anthony Carlisle]] use [[electrolysis]] to separate water into hydrogen and oxygen
* 1803 [[John Dalton]] introduces [[atomic theory|atomic]] ideas into [[chemistry]] and states that [[matter]] is composed of [[atomic weight|atoms of different weights]]
* 1805 (approximate time) [[Thomas Young (scientist)|Thomas Young]] conducts the [[double-slit experiment]] with light
* 1811 [[Amedeo Avogadro]] claims that equal volumes of gases should contain equal numbers of molecules
* 1815 [[William Prout]] [[Prout's hypothesis|hypothesizes]] that all matter is built up from [[hydrogen]], adumbrating the [[proton]];
* 1832 [[Michael Faraday]] states his laws of electrolysis
* 1838 [[Richard Laming]] hypothesized a subatomic particle carrying [[electric charge]];
* 1839 [[Alexandre Edmond Becquerel]] discovered the [[photovoltaic effect]] 
* 1858 [[Julius Plücker]] produced [[cathode ray]]s;
* 1871 [[Dmitri Mendeleyev]] systematically examines the [[periodic table]] and predicts the existence of [[gallium]], [[scandium]], and [[germanium]]
* 1873 [[Johannes van der Waals]] introduces the idea of weak attractive forces between molecules
* 1874 [[George Johnstone Stoney]] hypothesizes a minimum unit of electric charge. In 1891, he coins the word [[electron]] for it;
* 1885 [[Johann Balmer]] finds a mathematical expression for observed [[hydrogen line]] [[wavelength]]s
* 1886 [[Eugen Goldstein]] produced [[anode ray]]s;
* 1887 [[Heinrich Hertz]] discovers the [[photoelectric effect]]
* 1894 [[Lord Rayleigh]] and [[William Ramsay]] discover [[argon]] by [[spectroscopy|spectroscopically]] analyzing the gas left over after nitrogen and oxygen are removed from air
* 1895 [[William Ramsay]] discovers terrestrial [[helium]] by spectroscopically analyzing gas produced by decaying [[uranium]]
* 1896 [[Antoine Henri Becquerel]] discovers the [[radioactivity]] of uranium
* 1896 [[Pieter Zeeman]] studies the splitting of [[Fraunhofer lines|sodium D lines]] when sodium is held in a flame between strong [[magnet|magnetic poles]]
* 1897 [[J. J. Thomson]] discovered the [[electron]];
* 1897 [[Emil Wiechert]], [[Walter Kaufmann (physicist)|Walter Kaufmann]] and [[J.J. Thomson]] discover the [[electron]]
* 1898 [[Marie Curie|Marie]] and [[Pierre Curie]] discovered the existence of the radioactive elements [[radium]] and [[polonium]] in their research of [[pitchblende]]
* 1898 [[William Ramsay]] and [[Morris Travers]] discover [[neon]], and negatively charged [[beta particle]]s

==The age of quantum mechanics==
* 1887 [[Heinrich Rudolf Hertz]] discovers the [[photoelectric effect]] that will play a very important role in the development of the [[quantum mechanics|quantum theory]] with [[Albert Einstein|Einstein]]'s explanation of this effect in terms of ''[[quantum|quanta]]'' of light	
* 1896 [[Wilhelm Conrad Röntgen]] discovers the [[X-ray]]s while studying electrons in [[plasma (physics)|plasma]]; [[scattering]] X-rays—that were considered as 'waves' of high-energy [[electromagnetic radiation]]—[[Arthur Compton]] will be able to demonstrate in 1922 the 'particle' aspect of electromagnetic radiation.	
* 1899 [[Ernest Rutherford]] discovered the [[alpha particle|alpha]] and [[beta particle]]s emitted by [[uranium]];	
* 1900 [[Johannes Rydberg]] refines the expression for observed hydrogen line wavelengths	
* 1900 [[Max Planck]] states his [[quantum hypothesis]] and [[Planck's law of black-body radiation|blackbody radiation law]]	
* 1900 [[Paul Ulrich Villard|Paul Villard]] discovers [[gamma-ray]]s while studying uranium decay	
* 1902 [[Philipp Lenard]] observes that maximum [[Photoelectric effect|photoelectron]] energies are independent of illuminating intensity but depend on frequency	
* 1905 Albert Einstein explains the [[photoelectric effect]]	
* 1906 [[Charles Barkla]] discovers that each element has a characteristic [[X-ray]] and that the degree of penetration of these X-rays is related to the [[atomic weight]] of the element	
* 1908-1911 [[Jean Perrin]] proves the existence of [[atoms]] and [[molecules]] with [[Sedimentation equilibrium|experimental work]] to test [[Über die von der molekularkinetischen Theorie der Wärme geforderte Bewegung von in ruhenden Flüssigkeiten suspendierten Teilchen|Einstein's theoretical explanation]] of [[Brownian motion]]	
* 1909 [[Ernest Rutherford]] and [[Thomas Royds]] demonstrate that alpha particles are doubly [[ionization|ionized]] helium atoms	
* 1909 [[Hans Geiger]] and [[Ernest Marsden]] discover large angle deflections of alpha particles by thin metal foils
* 1911 [[Ernest Rutherford]] explains the [[Geiger–Marsden experiment]] by invoking a nuclear atom model and derives the [[Rutherford cross section]]	
* 1911 [[Ștefan Procopiu]] measures the magnetic dipole moment of the electron	
* 1912 [[Max von Laue]] suggests using [[crystal lattice]]s to [[diffraction|diffract]] X-rays	
* 1912 [[Walter Friedrich]] and [[Paul Knipping]] diffract X-rays in zinc blende	
* 1913 [[Henry Moseley]] shows that nuclear charge is the real basis for numbering the elements	
* 1913 [[Johannes Stark]] demonstrates that strong electric fields will split the Balmer spectral line series of hydrogen	
* 1913 [[Niels Bohr]] presents his [[Bohr model|quantum model of the atom]]<ref>{{Citation| author=Jammer, Max| author-link=Max Jammer| title=The conceptual development of quantum mechanics | publisher=McGraw-Hill | location=New York|year=1966|oclc=534562}}</ref>	
* 1913 [[Robert Millikan]] measures the [[Elementary charge|fundamental unit of electric charge]]	
* 1913 [[William Henry Bragg]] and [[William Lawrence Bragg]] work out the [[Bragg's law|Bragg condition]] for strong X-ray reflection	
* 1914 [[Ernest Rutherford]] suggests that the positively charged atomic nucleus contains [[proton]]s<ref>{{Cite book|url=https://books.google.com/books?id=NZsW0gj1OIcC&q=1914+Ernest+Rutherford+suggests+that+the+positively+charged+atomic+nucleus+contains+protons&pg=PA155|title=Evolution: The Universe, Life, Cultures, Ethnicity, Religion, Science, and Technology|last=Tivel|first=David E.|date=September 2012|publisher=Dorrance Publishing|isbn=9781434929747|language=en}}</ref>	
* 1914 [[James Franck]] and [[Gustav Hertz]] observe atomic excitation	
* 1915 [[Arnold Sommerfeld]] develops a modified [[Bohr Model|Bohr atomic model]] with elliptic orbits to explain relativistic fine structure	
* 1916 [[Gilbert N. Lewis]] and [[Irving Langmuir]] formulate an electron shell model of [[chemical bond]]ing	
* 1917 [[Albert Einstein]] introduces the idea of [[laser|stimulated radiation emission]]	
* 1918 Ernest Rutherford notices that, when [[alpha particle]]s were shot into [[nitrogen]] gas, his [[scintillation detector]]s showed the signatures of [[hydrogen]] nuclei.
* 1921 [[Alfred Landé]] introduces the [[Landé g-factor]]	
* 1922 [[Arthur Compton]] studies X-ray photon [[scattering]] by electrons demonstrating the 'particle' aspect of electromagnetic radiation.	
* 1922 [[Otto Stern]] and [[Walther Gerlach]] show "[[Stern–Gerlach experiment|spin quantization]]"	
* 1923 [[Lise Meitner]] discovers what is now referred to as the [[Auger electron|Auger process]]	
* 1924 [[John Lennard-Jones]] proposes a semiempirical [[interatomic force]] law	
* 1924 [[Louis de Broglie]] suggests that electrons may have wavelike properties in addition to their 'particle' properties; the ''[[wave–particle duality]]'' has been later extended to all fermions and bosons.	
* 1924 [[Santiago Antúnez de Mayolo]] proposes a neutron.	
* 1924 [[Satyendra Bose]] and Albert Einstein introduce [[Bose–Einstein statistics]]	
* 1925 [[George Uhlenbeck]] and [[Samuel Goudsmit]] postulate electron [[Spin (physics)|spin]]	
* 1925 [[Pierre Victor Auger|Pierre Auger]] discovers the [[Auger electron|Auger process]] (2 years after [[Lise Meitner]])	
* 1925 [[Werner Heisenberg]], [[Max Born]], and [[Pascual Jordan]] formulate quantum [[matrix mechanics]]	
* 1925 [[Wolfgang Pauli]] states the quantum [[Pauli exclusion principle|exclusion principle]] for electrons	
* 1926 [[Enrico Fermi]] discovers the [[spin–statistics theorem|spin–statistics]] connection, for particles that are now called 'fermions', such as the electron (of [[spin-1/2]]).	
* 1926 [[Erwin Schrödinger]] proves that the wave and matrix formulations of quantum theory are mathematically equivalent	
* 1926 [[Erwin Schrödinger]] states his nonrelativistic [[Schrödinger equation|quantum wave equation]] and formulates [[quantum mechanics|quantum wave mechanics]]	
* 1926 [[Gilbert N. Lewis]] introduces the term "''photon''", thought by him to be "''the carrier of [[radiant energy]].''"<ref>Gilbert N. Lewis. Letter to the editor of ''Nature'' (Vol. 118, Part 2, 18 December 1926, pp. 874–875).</ref><ref>[http://www.nobeliefs.com/photon.htm The origin of the word "photon"]</ref>	
* 1926 [[Oskar Klein]] and [[Walter Gordon (physicist)|Walter Gordon]] state their relativistic quantum wave equation, now the [[Klein–Gordon equation]]	
* 1926 [[Paul Dirac]] introduces [[Fermi–Dirac statistics]]	
* 1927 [[Charles Drummond Ellis]] (along with [[James Chadwick]] and colleagues) finally establish clearly that the beta decay spectrum is in fact continuous and not discrete, posing a problem that will later be solved by theorizing (and later discovering) the existence of the [[neutrino]].	
* 1927 [[Clinton Davisson]], [[Lester Germer]], and [[George Paget Thomson]] confirm the [[wave–particle duality|wavelike nature]] of electrons<ref>[http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/davger2.html The Davisson–Germer experiment, which demonstrates the wave nature of the electron]</ref>	
* 1927 [[L.H. Thomas|Thomas]] and [[Enrico Fermi|Fermi]] develop the [[Gas in a box|Thomas–Fermi model]]	
* 1927 [[Max Born]] [[probability amplitude|interprets the probabilistic nature]] of wavefunctions	
* 1927 [[Max Born]] and [[Robert Oppenheimer]] introduce the [[Born–Oppenheimer approximation]]	
* 1927 [[Walter Heitler]] and [[Fritz London]] introduce the concepts of [[valence bond theory]] and apply it to the [[hydrogen]] molecule.	
* 1927 [[Werner Heisenberg]] states the quantum [[uncertainty principle]]	
* 1928 [[Chandrasekhara Raman]] studies optical photon scattering by electrons	
* 1928 [[Charles G. Darwin]] and [[Walter Gordon (physicist)|Walter Gordon]] solve the [[Dirac equation]] for a Coulomb potential	
* 1928 [[Friedrich Hund]] and [[Robert S. Mulliken]] introduce the concept of [[molecular orbital]]	
* 1928 [[Paul Dirac]] states the [[Dirac equation]]	
* 1929 [[Nevill Mott]] derives the [[Mott scattering|Mott cross section]] for the Coulomb scattering of relativistic electrons	
* 1929 [[Oskar Klein]] discovers the [[Klein paradox]]	
* 1929 Oskar Klein and [[Yoshio Nishina]] derive the Klein–Nishina cross section for high energy photon scattering by electrons	
* 1930 [[Wolfgang Pauli]] postulated the [[neutrino]] to explain the energy spectrum of [[beta decay]]s;	
* 1930 [[Erwin Schrödinger]] predicts the [[zitterbewegung]] motion	
* 1930 [[Fritz London]] explains [[van der Waals force]]s as due to the interacting fluctuating [[Bond dipole moment|dipole moments]] between molecules	
* 1930 [[Paul Dirac]] introduces electron hole theory	
* 1931 [[Harold Urey]] discovers [[deuterium]] using evaporation concentration techniques and spectroscopy	
* 1931 [[Irène Joliot-Curie]] and [[Frédéric Joliot]] observe but misinterpret neutron scattering in paraffin	
* 1931 [[John Lennard-Jones]] proposes the [[Lennard-Jones potential|Lennard-Jones interatomic potential]]	
* 1931 [[Linus Pauling]] discovers resonance bonding and uses it to explain the high stability of symmetric planar molecules	
* 1931 [[Paul Dirac]] shows that [[charge quantization]] can be explained if [[magnetic monopole]]s exist	
* 1931 [[Wolfgang Pauli]] puts forth the [[neutrino]] hypothesis to explain the apparent violation of [[energy conservation]] in beta decay
* 1932 [[Carl D. Anderson]] discovers the [[positron]]	
* 1932 [[James Chadwick]] discovers the [[neutron]]	
* 1932 [[John Cockcroft]] and [[Ernest Walton]] split [[lithium]] and [[boron]] nuclei using proton bombardment	
* 1932 [[Werner Heisenberg]] presents the proton–neutron model of the nucleus and uses it to explain isotopes	
* 1933 [[Ernst Stueckelberg]] (1932), [[Lev Landau]] (1932), and [[Clarence Zener]] discover the [[Landau–Zener transition]]	
* 1933 [[Max Delbrück]] suggests that quantum effects will cause photons to be scattered by an external electric field	
* 1934 [[Enrico Fermi]] publishes a very successful model of beta decay in which neutrinos were produced.	
* 1934 [[Enrico Fermi]] suggests bombarding uranium atoms with neutrons to make a 93 proton element	
* 1934 [[Irène Joliot-Curie]] and [[Frédéric Joliot]] bombard [[aluminium]] atoms with alpha particles to create artificially radioactive [[phosphorus-30]]	
* 1934 [[Leó Szilárd]] realizes that [[nuclear chain reaction]]s may be possible	
* 1934 [[Lev Landau]] tells [[Edward Teller]] that non-linear molecules may have [[vibrational mode]]s which remove the [[degenerate energy level|degeneracy]] of an orbitally degenerate state ([[Jahn–Teller effect]])	
* 1934 [[Pavel Cherenkov]] reports that [[Cherenkov effect|light]] is emitted by relativistic particles traveling in a nonscintillating liquid	
* 1935 [[Albert Einstein]], [[Boris Podolsky]], and [[Nathan Rosen]] put forth the [[EPR paradox]]	
* 1935 [[Henry Eyring (chemist)|Henry Eyring]] develops the [[transition state]] theory	
* 1935 [[Hideki Yukawa]] presents a theory of the [[nuclear force]]<!-- note: what is NOW known as the “strong force” is different from the thing Yukawa theorized about! --> and predicts the scalar [[meson]]	
* 1935 [[Niels Bohr]] presents his analysis of the EPR paradox	
* 1936 [[Carl D. Anderson]] discovered the [[muon]] while he studied [[cosmic radiation]];	
* 1936 [[Alexandru Proca]] formulates the relativistic quantum field equations for a massive vector meson of spin-1 as a basis for nuclear forces	
* 1936 [[Eugene Wigner]] develops the theory of neutron absorption by atomic nuclei	
* 1936 [[Hermann Arthur Jahn]] and [[Edward Teller]] present their systematic study of the symmetry types for which the [[Jahn–Teller effect]] is expected<ref>A. Abragam and B. Bleaney. 1970. Electron Parmagnetic Resonance of Transition Ions, Oxford University Press: Oxford, U.K., p. 911</ref>	
* 1937	Carl Anderson proves experimentally the existence of the pion predicted by Yukawa's theory.
* 1937 [[Hans Hellmann]] finds the [[Hellmann–Feynman theorem]]	
* 1937 [[Seth Neddermeyer]], [[Carl David Anderson|Carl Anderson]], J.C. Street, and E.C. Stevenson discover [[muon]]s using [[cloud chamber]] measurements of [[cosmic ray]]s	
* 1939 [[Lise Meitner]] and [[Otto Robert Frisch]] determine that [[nuclear fission]] is taking place in the Hahn–Strassmann experiments	
* 1939 [[Otto Hahn]] and [[Fritz Strassmann]] bombard uranium salts with [[thermal neutron]]s and discover [[barium]] among the reaction products	
* 1939 [[Richard Feynman]] finds the Hellmann–Feynman theorem	
* 1942 [[Enrico Fermi]] makes the first controlled nuclear chain reaction	
* 1942 [[Ernst Stueckelberg]] introduces the propagator to positron theory and interprets positrons as negative energy electrons moving backwards through spacetime	

== Quantum field theory ==
* 1947 [[George Rochester|George Dixon Rochester]] and [[Clifford Charles Butler]] discovered the [[kaon]], the first [[strange particle]];
* 1947 [[Cecil Powell]], [[César Lattes]], and [[Giuseppe Occhialini]] discover the [[pion|pi meson]] by studying cosmic ray tracks
* 1947 [[Richard Feynman]] presents [[path integral formulation of quantum mechanics|his propagator approach to quantum electrodynamics]]<ref>{{cite book|last=Feynman |first=R.P.|year=2006 |orig-year=1985|title=[[QED: The Strange Theory of Light and Matter]]|publisher=[[Princeton University Press]]|isbn=0-691-12575-9}}</ref>
* 1947 [[Willis Lamb]] and [[Robert Retherford]] measure the [[Lamb shift#Lamb–Retherford experiment|Lamb–Retherford shift]]
* 1948 [[Hendrik Casimir]] predicts a rudimentary attractive [[Casimir effect|Casimir force]] on a parallel plate capacitor
* 1951 [[Martin Deutsch]] discovers [[positronium]]
* 1952 [[David Bohm]] propose [[Bohm interpretation|his interpretation of quantum mechanics]]
* 1953 [[Robert R. Wilson|Robert Wilson]] observes [[Delbruck scattering]] of 1.33 [[MeV]] gamma-rays by the electric fields of lead nuclei
* 1953 Charles H. Townes, collaborating with J. P. Gordon, and H. J. Zeiger, builds the first ammonia [[maser]]
* 1954 [[Chen Ning Yang]] and [[Robert Mills (physicist)|Robert Mills]] investigate a [[Yang–Mills theory|theory of]] hadronic [[isospin]] by demanding local [[gauge invariance]] under [[isotopic spin]] space rotations, the first non-Abelian [[gauge theory]]
* 1955 [[Owen Chamberlain]], [[Emilio Segrè]], [[Clyde Wiegand]], and [[Thomas Ypsilantis]] discover the [[antiproton]]
* 1955 and 1956 [[Murray Gell-Mann]] and [[Kazuhiko Nishijima]] independently derive the [[Gell-Mann–Nishijima formula]], which relates the [[baryon number]], the [[strangeness]], and the [[isospin]] of [[hadron]]s to the charge, eventually leading to the systematic categorization of hadrons and, ultimately, the [[quark model]] of hadron composition.
* 1956 [[Clyde Cowan]] and [[Frederick Reines]] discovered the (electron) [[neutrino]];
* 1956 [[Chen Ning Yang]] and [[Tsung Lee]] propose [[parity violation]] by the [[weak nuclear force]]
* 1956 [[Chien Shiung Wu]] discovers parity violation by the weak force in decaying cobalt
* 1956 [[Frederick Reines]] and [[Clyde Cowan]] detect [[antineutrino]]
* 1957 [[Bruno Pontecorvo]] postulated the flavor oscillation;
* 1957 [[Gerhart Luders]] proves the [[CPT theorem]]
* 1957 [[Richard Feynman]], [[Murray Gell-Mann]], [[Robert Marshak]], and [[E.C.G. Sudarshan]] propose a vector/axial vector (VA) [[Lagrangian (field theory)|Lagrangian]] for weak interactions.<ref>Richard Feynman; '''QED'''. Princeton University Press: Princeton, (1982)</ref><ref>Richard Feynman; ''Lecture Notes in Physics''. Princeton University Press: Princeton, (1986)</ref><ref>{{cite book|last=Feynman |first=R.P. |author-link=Richard Feynman|year=2001 |orig-year=1964|title=[[The Character of Physical Law]]|publisher=[[MIT Press]]|isbn=0-262-56003-8}}</ref><ref>{{cite book|last=Feynman |first=R.P.|year=2006 |orig-year=1985|title=[[QED: The Strange Theory of Light and Matter]]|publisher=[[Princeton University Press]]|isbn=0-691-12575-9}}</ref><ref>Schweber, Silvan S.; Q.E.D. and the men who made it: Dyson, Feynman, Schwinger, and Tomonaga, Princeton University Press (1994) {{ISBN|0-691-03327-7}}</ref><ref>Schwinger, Julian; Selected Papers on Quantum Electrodynamics, Dover Publications, Inc. (1958) {{ISBN|0-486-60444-6}}</ref>
* 1958 [[Marcus Sparnaay]] experimentally confirms the [[Casimir effect]]
* 1959 [[Yakir Aharonov]] and [[David Bohm]] predict the [[Aharonov–Bohm effect]]
* 1960 [[Robert G. Chambers|R.G. Chambers]] experimentally confirms the Aharonov–Bohm effect<ref>*{{cite book|last=Kleinert |first=H.|year=2008|title=Multivalued Fields in Condensed Matter, Electrodynamics, and Gravitation|url=http://users.physik.fu-berlin.de/~kleinert/public_html/kleiner_reb11/psfiles/mvf.pdf|publisher=[[World Scientific]]|isbn=978-981-279-170-2}}</ref>
* 1961 [[Jeffrey Goldstone]] considers the breaking of global phase symmetry
* 1961 [[Murray Gell-Mann]] and [[Yuval Ne'eman]] discover the [[Eightfold way (physics)|Eightfold Way]] patterns, the [[special unitary group|SU(3)]] group
* 1962 [[Leon Lederman]] shows that the electron neutrino is distinct from the muon neutrino
* 1963 [[Eugene Wigner]] discovers the fundamental roles played by quantum symmetries in atoms and molecules

==The formation and successes of the Standard Model==
* 1963 [[Nicola Cabibbo]] develops the mathematical matrix by which the first two (and ultimately three) generations of quarks can be predicted.
* 1964 [[Murray Gell-Mann]] and [[George Zweig]] propose the [[quark model|quark/aces model]]<ref>Yndurain, Francisco Jose;'' Quantum Chromodynamics: An Introduction to the Theory of Quarks and Gluons'', Springer Verlag, New York, 1983. {{ISBN|0-387-11752-0}}</ref><ref name="arxiv1999">[[Frank Wilczek]] (1999) "[https://arxiv.org/abs/hep-th/9803075 Quantum field theory]", ''Reviews of Modern Physics'' 71: S83–S95. Also doi=10.1103/Rev. Mod. Phys. 71.</ref>
* 1964 [[François Englert]], [[Robert Brout]], [[Peter Higgs]], [[Gerald Guralnik]], [[C. R. Hagen]], and [[Tom Kibble]] postulate that a fundamental quantum field, now called the [[Higgs field]], permeates space and, by way of the [[Higgs mechanism]], provides mass to all the elementary subatomic particles that interact with it. While the Higgs field is postulated to confer mass on quarks and leptons, it represents only a tiny portion of the masses of other subatomic particles, such as protons and neutrons. In these, gluons that bind quarks together confer most of the particle mass. The result is obtained independently by three groups: François Englert and Robert Brout; Peter Higgs, working from the ideas of Philip Anderson; and Gerald Guralnik, C. R. Hagen, and Tom Kibble.<ref>{{cite journal| first1=F. | last1=Englert | first2=R. | last2=Brout| year=1964| title=Broken Symmetry and the Mass of Gauge Vector Mesons| journal=[[Physical Review Letters]]| volume=13 | pages=321–323| doi=10.1103/PhysRevLett.13.321| bibcode=1964PhRvL..13..321E| issue=9| doi-access=free}}</ref><ref name="Peter W. Higgs 1964 508-509">{{cite journal| first1=P.W. | last1=Higgs| year=1964| title=Broken Symmetries and the Masses of Gauge Bosons| journal=[[Physical Review Letters]]| volume=13 | pages=508–509| doi=10.1103/PhysRevLett.13.508| bibcode=1964PhRvL..13..508H| issue=16| doi-access=free}}</ref><ref>{{cite journal| first1=G.S. | last1=Guralnik | first2=C.R. | last2=Hagen | first3=T.W.B. | last3=Kibble| year=1964| title=Global Conservation Laws and Massless Particles| journal=[[Physical Review Letters]]| volume=13 | pages=585–587| doi=10.1103/PhysRevLett.13.585| bibcode=1964PhRvL..13..585G| issue=20| doi-access=free}}</ref><ref>{{cite journal| first1=G.S. | last1=Guralnik| year=2009| title=The History of the Guralnik, Hagen and Kibble development of the Theory of Spontaneous Symmetry Breaking and Gauge Particles| journal=[[International Journal of Modern Physics A]]| volume=24 | pages=2601–2627| doi=10.1142/S0217751X09045431| arxiv=0907.3466|bibcode = 2009IJMPA..24.2601G| issue=14| s2cid=16298371}}</ref><ref>{{cite journal|first=T.W.B. | last=Kibble|year=2009|title=Englert–Brout–Higgs–Guralnik–Hagen–Kibble mechanism|journal=[[Scholarpedia]]|volume=4 |issue=1 |page=6441|doi=10.4249/scholarpedia.6441|bibcode = 2009SchpJ...4.6441K |doi-access=free}}</ref><ref>{{cite web|author1=M. Blume |author2=S. Brown |author3=Y. Millev |year=2008|url=http://prl.aps.org/50years/milestones#1964|title=Letters from the past, a PRL retrospective (1964)|publisher=[[Physical Review Letters]]|accessdate=2010-01-30}}</ref><ref>{{cite web|year=2010|url=http://www.aps.org/units/dpf/awards/sakurai.cfm|title=J. J. Sakurai Prize Winners|publisher=[[American Physical Society]]|accessdate=2010-01-30}}</ref>
* 1964 [[Murray Gell-Mann]] and [[George Zweig]] independently propose the [[quark|quark model]] of hadrons, predicting the arbitrarily named [[Up quark|up]], [[Down quark|down]], and [[Strange quark|strange]] quarks. Gell-Mann is credited with coining the term ''quark'', which he found in [[James Joyce]]'s book ''[[Finnegans Wake]]''.
* 1964 [[Sheldon Glashow]] and [[James Bjorken]] predict the existence of the charm quark. The addition is proposed because it allows for a better description of the [[weak interaction]] (the mechanism that allows quarks and other particles to decay), equalizes the number of known [[quarks]] with the number of known [[leptons]], and implies a mass formula that correctly reproduced the masses of the known [[mesons]].
* 1964 [[John Stewart Bell]] shows that all local [[hidden variable theories]] must satisfy [[Bell's inequality]]
* 1964 [[Peter Higgs]] considers the breaking of local phase symmetry
* 1964 [[Val Fitch]] and [[James Cronin]] observe CP violation by the weak force in the decay of K mesons
* 1967 [[Bruno Pontecorvo]] postulated [[neutrino oscillation]];
* 1967 [[Steven Weinberg]] and [[Abdus Salam]] publish papers in which they describe [[Yang–Mills theory]] using the SU(2) X U(1) [[supersymmetry]] group, thereby yielding a mass for the W particle of the [[weak interaction]] via [[spontaneous symmetry breaking]].
* 1967 [[Steven Weinberg]] puts forth his electroweak model of [[lepton]]s<ref>Weinberg, Steven; The Quantum Theory of Fields: Foundations (vol. I), Cambridge University Press (1995) {{ISBN|0-521-55001-7}}. The first chapter (pp. 1–40) of Weinberg's monumental treatise gives a brief history of Q.F.T., pp. 608.</ref><ref name="autogenerated489">Weinberg, Steven; The Quantum Theory of Fields: Modern Applications (vol. II), Cambridge University Press:Cambridge, U.K. (1996) {{ISBN|0-521-55001-7}}, pp. 489.</ref>
* 1968 [[Stanford University]]: [[Deep inelastic scattering]] experiments at the [[Stanford Linear Accelerator Center]] (SLAC) show that the [[proton]] contains much smaller, point-like objects and is therefore not an elementary particle. Physicists at the time are reluctant to identify these objects with [[quarks]], instead calling them ''partons'' — a term coined by Richard Feynman. The objects that are observed at SLAC will later be identified as [[Up quark|up]] and [[Down quark|down]] quarks. Nevertheless, "parton" remains in use as a collective term for the constituents of [[hadrons]] (quarks, [[antiquarks]], and [[gluons]]). The existence of the [[strange quark]] is indirectly validated by the SLAC's scattering experiments: not only is it a necessary component of Gell-Mann and Zweig's three-quark model, but it provides an explanation for the [[kaon]] (K) and [[pion]] (π) hadrons discovered in cosmic rays in 1947.
* 1969 [[John Clauser]], [[Michael Horne (physicist)|Michael Horne]], [[Abner Shimony]] and [[Richard Holt (physicist)|Richard Holt]] propose a polarization correlation test of [[Bell's inequality]]
* 1970 [[Sheldon Glashow]], [[John Iliopoulos]], and [[Luciano Maiani]] propose the charm quark
* 1971 [[Gerard 't Hooft]] shows that the Glashow-Salam-Weinberg electroweak model can be renormalized<ref>* [[Gerard 't Hooft]] (2007) "[http://www.phys.uu.nl/~thooft/lectures/basisqft.pdf The Conceptual Basis of Quantum Field Theory]" in Butterfield, J., and [[John Earman]], eds., ''Philosophy of Physics, Part A''. Elsevier: 661-730.</ref>
* 1972 [[Stuart Freedman]] and [[John Clauser]] perform the first polarization correlation test of [[Bell's inequality]]
* 1973 [[Frank Wilczek|Frank Anthony Wilczek]] discover the quark asymptotic freedom in the theory of strong interactions; receives the [[Lorentz Medal]] in 2002, and the Nobel Prize in Physics in 2004 for his discovery and his subsequent contributions to [[quantum chromodynamics]].<ref>{{cite journal|arxiv=hep-th/9803075|doi=10.1103/RevModPhys.71.S85|title=Quantum field theory|year=1999|last1=Wilczek|first1=Frank|journal=Reviews of Modern Physics|volume=71|issue=2|pages=S85–S95|bibcode = 1999RvMPS..71...85W |s2cid=279980 }}</ref>
* 1973 [[Makoto Kobayashi (physicist)|Makoto Kobayashi]] and [[Toshihide Maskawa]] note that the experimental observation of [[CP violation]] can be explained if an additional pair of [[quarks]] exist. The two new quarks are eventually named [[Top quark|top]] and [[Bottom quark|bottom]].
* 1973 [[David Politzer]] and [[Frank Wilczek|Frank Anthony Wilczek]] propose the [[asymptotic freedom]] of quarks<ref name="arxiv1999"/>
* 1974 [[Burton Richter]] and [[Samuel Ting]]: Charm quarks are produced almost simultaneously by two teams in November 1974 (see [[November Revolution (physics)|November Revolution]]) — one at [[SLAC]] under Burton Richter, and one at [[Brookhaven National Laboratory]] under Samuel Ting. The charm quarks are observed bound with charm [[antiquarks]] in [[mesons]]. The two discovering parties independently assign the discovered meson two different symbols, J and ψ; thus, it becomes formally known as the [[J/ψ meson]]. The discovery finally convinces the physics community of the quark model's validity.
* 1974 [[Robert J. Buenker]] and [[Sigrid D. Peyerimhoff]] introduce the [[multireference configuration interaction]] method.
* 1975 [[Martin Perl]] discovers the [[tau lepton]]
* 1977 [[Leon Lederman]] observes the [[bottom quark]] with his team at [[Fermilab]].<ref name=fermilabDiscoveries>{{Cite web|title=Fermilab {{!}} Science {{!}} Particle Physics {{!}} Key Discoveries|url=https://www.fnal.gov/pub/science/particle-physics/key-discoveries.html|access-date=2020-08-26|website=www.fnal.gov}}</ref> This discovery is a strong indicator of the [[top quark]]'s existence: without the top quark, the bottom quark would be without a partner that is required by the mathematics of the theory.
* 1977 [[Martin Lewis Perl]] discovered the [[tau lepton]] after a series of experiments;
* 1977 [[Steve Herb]] finds the [[upsilon particle|upsilon resonance]] implying the existence of the [[bottom quark|beauty/bottom quark]]
* 1979 [[Gluon]] observed indirectly in [[three-jet event]]s at [[DESY]];
* 1982 [[Alain Aspect]], J. Dalibard, and G. Roger perform a polarization correlation test of [[Bell's inequality]] that rules out conspiratorial polarizer communication
* 1983 [[Carlo Rubbia]] and [[Simon van der Meer]] discovered the [[W and Z bosons]];
* 1983 [[Carlo Rubbia]], [[Simon van der Meer]], and the CERN UA-1 collaboration find the [[W and Z bosons|W and Z intermediate vector bosons]]<ref>Pais, Abraham; Inward Bound: Of Matter & Forces in the Physical World, Oxford University Press (1986) {{ISBN|0-19-851997-4}} Written by a former Einstein assistant at Princeton, this is a beautiful detailed history of modern fundamental physics, from 1895 (discovery of X-rays) to 1983 (discovery of vectors bosons at C.E.R.N.)</ref>
* 1989 The Z intermediate vector boson [[resonance#Theory|resonance width]] indicates three [[generation (particle physics)|quark–lepton generations]]
* 1994 The [[CERN]] [[LEAR]] [[Crystal Barrel Experiment]] justifies the existence of [[glueball]]s ([[exotic meson]]).
* 1995 The [[top quark]] is finally observed by a team at [[Fermilab]] after an 18-year search.<ref name=fermilabDiscoveries /> It has a mass much greater than had been previously expected — almost as great as a gold atom.
* 1995 The [[D0 experiment|D0]] and [[Collider Detector at Fermilab|CDF]] experiments at the [[Fermilab]] [[Tevatron]] discover the [[top quark]].
* 1998 – The [[Super-Kamiokande]] (Japan) detector facility reports experimental evidence for [[neutrino oscillation]]s, implying that at least one neutrino has mass.<ref name="FukudaHayakawa1998">{{cite journal |first=Y. |last=Fukuda |collaboration=Super-Kamiokande Collaboration |title=Evidence for Oscillation of Atmospheric Neutrinos |journal=Physical Review Letters |volume=81 |issue=8 |date=24 August 1998 |pages=1562–1567 |doi=10.1103/PhysRevLett.81.1562 |display-authors=etal |arxiv=hep-ex/9807003 |bibcode=1998PhRvL..81.1562F}}</ref>
* 1998 [[Super-Kamiokande]] (Japan) observes evidence for [[neutrino oscillation]]s, implying that at least one neutrino has mass.
* 1999 [[Ahmed Zewail]] wins the Nobel prize in chemistry for his work on [[femtochemistry]] for atoms and molecules.<ref>{{cite web|title=Press Release: The 1999 Nobel Prize in Chemistry|url=https://www.nobelprize.org/nobel_prizes/chemistry/laureates/1999/press.html|access-date=30 June 2013|date=12 October 1999}}</ref>
* 2000 scientists at  [[Fermilab]] announce the first direct evidence for the [[tau neutrino]], the third kind of neutrino in particle physics.<ref name=fermilabDiscoveries />
* 2000 [[CERN]] announced [[Quark–gluon plasma|quark-gluon plasma]], a new phase of matter.<ref>{{Cite web|title=New State of Matter created at CERN|url=https://home.cern/news/press-release/cern/new-state-matter-created-cern|website=CERN|language=en|access-date=2020-05-22}}</ref>
* 2001 the [[Sudbury Neutrino Observatory]] (Canada) confirm the existence of neutrino oscillations. [[Lene Hau]] stops a beam of light completely in a [[Bose–Einstein condensate]].<ref>{{cite web|url=http://www.physicscentral.com/explore/people/hau.cfm |title=Lene Hau |publisher=Physicscentral.com |date= |accessdate=2013-01-30}}</ref>
* 2001 The [[Sudbury Neutrino Observatory]] (Canada) confirms the existence of [[neutrino oscillations]].
* 2005 the [[RHIC]] accelerator of [[Brookhaven National Laboratory]] generates a "perfect" fluid, perhaps the [[quark–gluon plasma]].<ref>{{Cite web|title=RHIC Scientists Serve Up 'Perfect' Liquid|url=https://www.bnl.gov/newsroom/news.php?a=110303|access-date=2020-08-26|website=Brookhaven National Laboratory|language=en}}</ref>
* 2010 The [[Large Hadron Collider]] at [[CERN]] begins operation with the primary goal of searching for the [[Higgs boson]].
* 2012 [[Higgs boson]]-like particle discovered at [[CERN]]'s [[Large Hadron Collider]] (LHC).<ref>{{Cite web|title=CERN experiments observe particle consistent with long-sought Higgs boson|url=https://home.cern/news/press-release/cern/cern-experiments-observe-particle-consistent-long-sought-higgs-boson|website=CERN|language=en|access-date=2020-05-22}}</ref>
* 2014 The [[LHCb experiment]] observes particles consistent with [[tetraquark]]s and [[pentaquark]]s <ref>{{cite journal| author1=LHCb Collaboration |title=Observation of the Resonant Character of the Z ( 4430 ) − State |journal=Physical Review Letters |date=4 June 2014 |volume=112 |issue=22 |page=222002 |doi=10.1103/PhysRevLett.112.222002|pmid=24949760 |s2cid=904429 |hdl=2445/133080 |hdl-access=free }}</ref>
* 2014 The [[T2K experiment|T2K]] and [[OPERA experiment]] observe the appearance of [[electron neutrino]]s and [[Tau neutrino]]s in a [[muon neutrino]] [[Accelerator neutrino|beam]]<ref>{{cite journal |author1=((T2K Collaboration)) |title=Observation of Electron Neutrino Appearance in a Muon Neutrino Beam |journal=Physical Review Letters |date=10 February 2014 |volume=112 |issue=6 |pages=061802 |doi=10.1103/PhysRevLett.112.061802|pmid=24580687 |arxiv=1311.4750 |bibcode=2014PhRvL.112f1802A |hdl=10044/1/20051 |s2cid=2586182 |hdl-access=free }}</ref><ref>{{cite journal |author1=OPERA Collaboration |title=Observation of tau neutrino appearance in the CNGS beam with the OPERA experiment |journal=Progress of Theoretical and Experimental Physics |date=28 October 2014 |volume=2014 |issue=10 |pages=101C01 |doi=10.1093/ptep/ptu132|doi-access=free |arxiv=1407.3513 }}</ref>

==See also==
* [[Chronology of the universe]]
* [[History of subatomic physics]]
* [[History of quantum mechanics]]
* [[History of quantum field theory]]
* [[History of the molecule]]
* [[History of thermodynamics]]
* [[History of chemistry]]
* [[Golden age of physics]]
* [[Timeline of cosmological theories]]
* [[Timeline of particle physics technology]]

==References==
{{Reflist}}

==External links==
* [http://www.alainconnes.org/ Alain Connes official website] with [http://www.alainconnes.org/en/downloads.php downloadable papers.]
* [http://resonaances.blogspot.com/2007/02/alain-connes-standard-model.html Alain Connes's Standard Model.]
* [http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/The_Quantum_age_begins.html A History of Quantum Mechanics] {{Webarchive|url=https://web.archive.org/web/20191028220722/http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/The_Quantum_age_begins.html |date=2019-10-28 }}
* [http://www.oberlin.edu/physics/dstyer/StrangeQM/history.html A Brief History of Quantum Mechanics]

{{Particles}}
{{History of physics}}

{{DEFAULTSORT:Timeline Of Atomic And Subatomic Physics}}
[[Category:Particle physics]]
[[Category:Nuclear physics]]
[[Category:Atomic physics]]
[[Category:Physics timelines|Atomic]]