Timeline of particle discoveries

| William Herschel discovers "heat rays" (now known as infrared)

| Johann Wilhelm Ritter made the hallmark observation that invisible rays just beyond the violet end of the visible spectrum were especially effective at lightening silver chloride-soaked paper. He called them "de-oxidizing rays" to emphasize chemical reactivity and to distinguish them from "heat rays" at the other end of the invisible spectrum (both of which were later determined to be photons). The more general term "chemical rays" was adopted shortly thereafter to describe the oxidizing rays, and it remained popular throughout the 19th century. The terms chemical and heat rays were eventually dropped in favor of ultraviolet and infrared radiation, respectively.

{{Cite journal

| last = Hockberger

| first = P. E.

| title = A history of ultraviolet photobiology for humans, animals and microorganisms

| journal = Photochem. Photobiol.

| volume = 76

| issue =6

| pages = 561–579

| year = 2002

| url = http://www.bioone.org/doi/abs/10.1562/0031-8655%282002%29076%3C0561%3AAHOUPF%3E2.0.CO%3B2

| doi =10.1562/0031-8655(2002)0760561AHOUPF2.0.CO2

| pmid = 12511035

| s2cid = 222100404

| issn = 0031-8655

| url-access = subscription

}}

| Discovery of the ultraviolet radiation below 200 nm, named vacuum ultraviolet (later identified as photons) because it is strongly absorbed by air, by the German physicist Victor SchumannThe ozone layer protects humans from this.

{{Cite journal

| last = Lyman

| first = T.

| title = Victor Schumann

| journal = Astrophysical Journal

| volume = 38

| pages = 1–4

| year = 1914

| bibcode = 1914ApJ....39....1L

| doi =10.1086/142050

| doi-access = free

}}

|X-ray produced by Wilhelm Röntgen (later identified as photons)

{{cite journal

| author = W.C. Röntgen

| year = 1895

| title = Über ein neue Art von Strahlen. Vorlaufige Mitteilung

| journal = Sitzber. Physik. Med. Ges.

| volume = 137 | pages = 1

| url = http://web.lemoyne.edu/~giunta/roentgen.html

}} as translated in {{cite journal

|author=A. Stanton

|year=1896

|title=On a New Kind of Rays

|journal=Nature

|volume=53

|issue=1369 |pages=274–276

|doi=10.1038/053274b0

|bibcode = 1896Natur..53R.274. |doi-access=free

}}

| Electron discovered by J. J. Thomson

{{cite journal

| author = J.J. Thomson

| year = 1897

| title = Cathode Rays

| url = http://web.lemoyne.edu/~GIUNTA/thomson1897.html

| journal = Philosophical Magazine

| volume = 44 | pages = 293–316

| doi=10.1080/14786449708621070

| issue=269

| url-access = subscription

}}

| Alpha particle discovered by Ernest Rutherford in uranium radiation

{{cite journal

| author = E. Rutherford

| year = 1899

| title = Uranium Radiation and the Electrical Conduction Produced by it

| volume = 47 | pages = 109–163

| journal = Philosophical Magazine

| doi = 10.1080/14786449908621245

| issue=284

| url = https://zenodo.org/record/1431247

}}

| Gamma ray (a high-energy photon) discovered by Paul Villard in uranium decay

{{cite journal

| author = P. Villard

| year = 1900

| title = Sur la Réflexion et la Réfraction des Rayons Cathodiques et des Rayons Déviables du Radium

| journal = Comptes Rendus de l'Académie des Sciences

| volume = 130 | pages = 1010

}}

| Atomic nucleus identified by Ernest Rutherford, based on scattering observed by Hans Geiger and Ernest Marsden

{{cite journal

| year = 1911

| author = E. Rutherford

| title = The Scattering of α- and β- Particles by Matter and the Structure of the Atom

| journal = Philosophical Magazine

| volume = 21 | pages = 669–688

| doi = 10.1080/14786440508637080

| issue=125

}}

| Proton discovered by Ernest Rutherford

{{cite journal

| author = E. Rutherford

| year = 1919

| title = Collision of α Particles with Light Atoms IV. An Anomalous Effect in Nitrogen

| journal = Philosophical Magazine

| volume = 37 | pages = 581

}}

| Deuteron discovered by Harold Urey{{cite journal | last1 = Brickwedde | first1 = Ferdinand G. | title = Harold Urey and the discovery of deuterium | journal = Physics Today | volume = 35 | page = 34 | year = 1982 | doi = 10.1063/1.2915259|bibcode = 1982PhT....35i..34B | issue = 9 }}{{cite journal | last1 =Urey | first1 =Harold | last2 =Brickwedde | first2 =F. | last3 =Murphy | first3 =G. | title =A Hydrogen Isotope of Mass 2 | journal =Physical Review | volume =39 | issue =1 | pages =164–165 | year =1932 | doi =10.1103/PhysRev.39.164|bibcode = 1932PhRv...39..164U | doi-access =free }} (predicted by Rutherford in 1920

{{cite journal

| author = E. Rutherford

| year = 1920

| title = Nuclear Constitution of Atoms

| journal = Proceedings of the Royal Society A

| volume = 97 | pages = 374–400

| doi = 10.1098/rspa.1920.0040

|bibcode = 1920RSPSA..97..374R

| issue=686| doi-access = free

}})

| Neutron discovered by James Chadwick

{{cite journal

| author = J. Chadwick

| year = 1932

| title = Possible Existence of a Neutron

| journal = Nature

| volume = 129

| issue = 3252 | pages = 312

| doi = 10.1038/129312a0

|bibcode = 1932Natur.129Q.312C | s2cid = 4076465

| doi-access = free

}} (predicted by Rutherford in 1920) {{Main|Discovery of the neutron}}

| Antielectron (or positron), the first antiparticle, discovered by Carl D. Anderson

{{cite journal

| author = C.D. Anderson

| year = 1932

| title = The Apparent Existence of Easily Deflectable Positives

| journal = Science

| volume = 76 | issue = 1967 | pages = 238–9

| doi = 10.1126/science.76.1967.238

| pmid = 17731542

|bibcode = 1932Sci....76..238A }} (proposed by Paul Dirac in 1927 and by Ettore Majorana in 1928)

| Muon (or mu lepton) discovered by Seth Neddermeyer, Carl D. Anderson, J.C. Street, and E.C. Stevenson, using cloud chamber measurements of cosmic rays

{{cite journal

|author1=S.H. Neddermeyer |author2=C.D. Anderson | year = 1937

| title = Note on the nature of Cosmic-Ray Particles

| journal = Physical Review

| pages = 884–886

| issue = 10 | volume = 51

| doi = 10.1103/PhysRev.51.884

|bibcode = 1937PhRv...51..884N |url=https://authors.library.caltech.edu/8618/1/NEDpr37.pdf }} (it was mistaken for the pion until 1947

{{cite journal

|author1=M. Conversi |author2=E. Pancini |author3=O. Piccioni | year = 1947

| title = On the Disintegration of Negative Muons

| journal = Physical Review

| pages = 209–210

| issue = 3 | volume = 71

| doi = 10.1103/PhysRev.71.209

|bibcode = 1947PhRv...71..209C }})

| Pion (or pi meson) discovered by C. F. Powell's group, including César Lattes (first author) and Giuseppe Occhialini (predicted by Hideki Yukawa in 1935

{{cite journal

| author = H. Yukawa

| year = 1935

| title = On the Interaction of Elementary Particles

| journal = Proceedings of the Physico-Mathematical Society of Japan

| volume = 17 | pages = 48

}})

| Kaon (or K meson), the first strange particle, discovered by George Dixon Rochester and Clifford Charles Butler

{{cite journal

|author1=G.D. Rochester |author2=C.C. Butler | year = 1947

| title = Evidence for the Existence of New Unstable Elementary Particles

| journal = Nature

| volume = 160

| issue = 4077 | pages = 855–857

| doi = 10.1038/160855a0

|pmid=18917296 |bibcode = 1947Natur.160..855R |s2cid=33881752 }}

| Lambda baryon (or lambda baryon) discovered during a study of cosmic-ray interactions[http://hyperphysics.phy-astr.gsu.edu/Hbase/Particles/quark.html#c4 The Strange Quark]

| Antiproton discovered by Owen Chamberlain, Emilio Segrè, Clyde Wiegand, and Thomas Ypsilantis

{{cite journal

|author1=O. Chamberlain |author2=E. Segrè |author3=C. Wiegand |author4=T. Ypsilantis |year=1955

|title=Observation of Antiprotons

|journal=Physical Review

|volume=100

|issue=3 |pages=947–950

|doi=10.1103/PhysRev.100.947

|bibcode = 1955PhRv..100..947C |url=https://escholarship.org/content/qt46p0z8w7/qt46p0z8w7.pdf?t=lnq112}}

| Electron neutrino detected by Frederick Reines and Clyde Cowan (proposed by Wolfgang Pauli in 1930 to explain the apparent violation of conservation of energy in beta decay)

{{cite journal

|author1=F. Reines |author2=C.L. Cowan |year=1956

|title=The Neutrino

|journal=Nature

|volume=178

|issue=4531 |pages=446–449

|doi=10.1038/178446a0

|bibcode = 1956Natur.178..446R |s2cid=4293703 }} At the time it was simply referred to as neutrino since there was only one known neutrino.

{{Main|Cowan–Reines neutrino experiment}}

| Muon neutrino (or mu neutrino) shown to be distinct from the electron neutrino by a group headed by Leon Lederman

{{cite journal

|author=G. Danby|year=1962

|title=Observation of High-Energy Neutrino Reactions and the Existence of Two Kinds of Neutrinos

|journal=Physical Review Letters

|volume=9

|issue=1 |pages=36–44

|doi=10.1103/PhysRevLett.9.36

|bibcode=1962PhRvL...9...36D

|display-authors=etal}}

| Omega baryon{{Cite web |title=Home {{!}} CERN Teacher Programmes |url=https://teacher-programmes.web.cern.ch/ |access-date=2023-04-20 |website=teacher-programmes.web.cern.ch}} and Xi baryon discovery at Brookhaven National Laboratory

{{cite web

|author=R. Nave

|url=http://hyperphysics.phy-astr.gsu.edu/hbase/particles/xi.html

|title=The Xi Baryon

|publisher=HyperPhysics

|access-date=20 June 2009

}}

| Partons (internal constituents of hadrons) observed in deep inelastic scattering experiments between protons and electrons at SLAC;

{{cite journal

|author=E.D. Bloom|year=1969

|title=High-Energy Inelastic e–p Scattering at 6° and 10°

|journal=Physical Review Letters

|volume=23

|issue=16 |pages=930–934

|doi=10.1103/PhysRevLett.23.930

|bibcode=1969PhRvL..23..930B

|display-authors=etal|doi-access=free}}

{{cite journal|author=M. Breidenbach|author-link=Martin Breidenbach|display-authors=etal|year=1969|title=Observed Behavior of Highly Inelastic Electron-Proton Scattering|journal=Physical Review Letters|volume=23|issue=16|pages=935–939|bibcode=1969PhRvL..23..935B|doi=10.1103/PhysRevLett.23.935|osti=1444731|s2cid=2575595 }} this was eventually associated with the quark model (predicted by Murray Gell-Mann and George Zweig in 1964) and thus constitutes the discovery of the up quark, down quark, and strange quark.

| J/ψ meson discovered by groups headed by Burton Richter and Samuel Ting, demonstrating the existence of the charm quark

{{cite journal

|author=J.J. Aubert|year=1974

|title=Experimental Observation of a Heavy Particle J

|journal=Physical Review Letters

|volume=33

|issue=23 |pages=1404–1406

|doi=10.1103/PhysRevLett.33.1404

|bibcode=1974PhRvL..33.1404A

|display-authors=etal|doi-access=free}}

{{cite journal

|author=J.-E. Augustin|year=1974

|title=Discovery of a Narrow Resonance in e⁺e⁻ Annihilation

|journal=Physical Review Letters

|volume=33

|issue=23 |pages=1406–1408

|doi=10.1103/PhysRevLett.33.1406

|bibcode=1974PhRvL..33.1406A

|display-authors=etal|doi-access=free}} (proposed by James Bjorken and Sheldon Glashow in 1964

{{cite journal

|author1=B.J. Bjørken |author2=S.L. Glashow |year=1964

|journal=Physics Letters

|volume=11

|issue=3 |pages=255–257

|title=Elementary Particles and SU(4)

|doi=10.1016/0031-9163(64)90433-0

|bibcode = 1964PhL....11..255B }})

| Tau discovered by a group headed by Martin Perl

{{cite journal

|author=M.L. Perl|year=1975

|title=Evidence for Anomalous Lepton Production in e⁺–e⁻ Annihilation

|journal=Physical Review Letters

|volume=35

|issue=22 |pages=1489–1492

|doi=10.1103/PhysRevLett.35.1489

|bibcode=1975PhRvL..35.1489P

|display-authors=etal}}

| Upsilon meson discovered at Fermilab, demonstrating the existence of the bottom quark

{{cite journal

|author=S.W. Herb|year=1977

|title=Observation of a Dimuon Resonance at 9.5 GeV in 400-GeV Proton-Nucleus Collisions

|journal=Physical Review Letters

|volume=39

|issue=5 |pages=252–255

|doi=10.1103/PhysRevLett.39.252

|bibcode=1977PhRvL..39..252H

|osti=1155396

|display-authors=etal}} (proposed by Kobayashi and Maskawa in 1973)

| Gluon observed indirectly in three-jet events at DESY

{{cite journal

|author=D.P. Barber|year=1979

|title=Discovery of Three-Jet Events and a Test of Quantum Chromodynamics at PETRA

|journal=Physical Review Letters

|volume=43

|issue=12 |pages=830–833

|doi=10.1103/PhysRevLett.43.830

|bibcode=1979PhRvL..43..830B

|s2cid=13903005

|display-authors=etal}}

| W and Z bosons discovered by Carlo Rubbia, Simon van der Meer, and the CERN UA1 collaboration

{{cite journal

|author=J.J. Aubert et al. (European Muon Collaboration)

|year=1983

|title=The ratio of the nucleon structure functions F₂^N for iron and deuterium

|journal=Physics Letters B

|volume=123

|issue=3–4 |pages=275–278

|doi=10.1016/0370-2693(83)90437-9

|bibcode = 1983PhLB..123..275A |url=https://cds.cern.ch/record/142300/files/cer-000053387.pdf

}}

{{cite journal

|author=G. Arnison et al. (UA1 collaboration)

|year=1983

|title=Experimental observation of lepton pairs of invariant mass around {{val|95|u=GeV/c2}} at the CERN SPS collider

|journal=Physics Letters B

|volume=126

|issue=5 |pages=398–410

|doi=10.1016/0370-2693(83)90188-0

|bibcode = 1983PhLB..126..398A |url=https://cds.cern.ch/record/163857

}} (predicted in detail by Sheldon Glashow, Mohammad Abdus Salam, and Steven Weinberg)

| Top quark discovered at Fermilab

{{cite journal

|author = F. Abe et al. (CDF collaboration)

|year = 1995

|title = Observation of Top quark production in {{Overline|p}}–p Collisions with the Collider Detector at Fermilab

|journal = Physical Review Letters

|volume = 74 |pages = 2626–2631

|doi=10.1103/PhysRevLett.74.2626

|pmid=10057978

|issue=14

|bibcode=1995PhRvL..74.2626A

|arxiv = hep-ex/9503002 |s2cid = 119451328

}}

{{cite journal

| author = S. Arabuchi et al. (D0 collaboration)

| year = 1995

| title = Observation of the Top Quark

| journal = Physical Review Letters

| volume = 74 | pages = 2632–2637

| doi = 10.1103/PhysRevLett.74.2632

| pmid=10057979

| issue=14

| bibcode=1995PhRvL..74.2632A

|arxiv = hep-ex/9503003 | s2cid = 42826202

}}

| Antihydrogen produced and measured by the LEAR experiment at CERN

{{cite journal

|author = G. Baur|year = 1996

|title = Production of Antihydrogen

|journal = Physics Letters B

|volume = 368

|issue = 3

|pages = 251–258

|doi = 10.1016/0370-2693(96)00005-6

|bibcode = 1996PhLB..368..251B |display-authors=etal|citeseerx = 10.1.1.38.7538

}}

| Quark-gluon fireball discovered at CERN{{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}}

| Tau neutrino first observed directly at Fermilab

{{cite press release

|publisher=Fermilab

|date=20 July 2000

|title=Physicists Find First Direct Evidence for Tau Neutrino at Fermilab

|url=http://www.fnal.gov/pub/presspass/press_releases/donut.html

|access-date=20 March 2010

}}

| Antihelium-4 produced and measured by the STAR detector; the first particle to be discovered by the experiment

| A particle exhibiting most of the predicted characteristics of the Higgs boson discovered by researchers conducting the Compact Muon Solenoid and ATLAS experiments at CERN's Large Hadron Collider

{{cite news

| last=Boyle

| first=Alan

| title=Milestone in Higgs quest: Scientists find new particle

| newspaper=MSNBC

| publisher=MSNBC

| date=4 July 2012

| url=http://cosmiclog.msnbc.msn.com/_news/2012/07/04/12554487-milestone-in-higgs-quest-scientists-find-new-particle?lite&ocid=ansmsnbc11

| archive-url=https://web.archive.org/web/20120707031257/http://cosmiclog.msnbc.msn.com/_news/2012/07/04/12554487-milestone-in-higgs-quest-scientists-find-new-particle?lite&ocid=ansmsnbc11

| url-status=dead

| archive-date=7 July 2012

| access-date=5 July 2012}}