deconstruction: standard model discoveries

elementary types of particles form the basis for the theoretical framework known as the Sixteen Standard Model of fundamental particles and forces. J.J. Thomson discovered the electron in 1897, while scientists at Fermilab saw the first direct interaction of a tau neutrino with matter less than 10 years ago. This graphic names the 16 particle types and shows when and where they were discovered. These particles also exist in the form of antimatter particles, with the same mass and the opposite electric charge. Together, they account for about 300 subatomic particles observed in experiments so far. The Standard Model also predicts the Higgs boson, which still eludes experimental detection. Experiments at Fermilab and CERN could see the first signals for this particle in the next couple of years. Other funda- mental particles must exist, too. The Standard Model does not account for dark matter, which appears to make up 83 percent of all matter in the universe.

1968: SLAC 1974: Brookhaven & SLAC 1995: Fermilab 1979: DESY u c t g

up quark charm quark top quark gluon

1968: SLAC 1947: Manchester University 1977: Fermilab 1923: Washington University* d s b γ down quark strange quark bottom quark photon

1956: Savannah River Plant 1962: Brookhaven 2000: Fermilab 1983: CERN

νe νμ ντ W electron neutrino muon neutrino tau neutrino W boson

1897: Cavendish Laboratory 1937 : Caltech and Harvard 1976: SLAC 1983: CERN e μ τ Z electron muon tau Z boson

*Scientists suspected for several hundred years that light consists of particles. Many experiments and theoretical explana- tions have led to the discovery of the photon, which explains both wave and particle properties of light.

30 Nobel awarded:2008 Discovery made:1973 the prizewithYoichiro Nambu) and Toshihide Maskawa(sharing Laureates: MakotoKobayashi containing astrangequark metry-violating behaviorofparticles and topquarkstoexplain thesym- Nobel work: Nobel awarded:1957 Discovery made:1956 Chen NingYang Laureates: Tsung-Dao Lee and as welldecayofstrangeparticles decay signaturesinbeta experimental mirror symmetry, which leadsto weak nuclearforceviolatesparity, or Nobel work: 1988 Nobel awarded:1988 Discovery made:1962 andJack Steinberger Schwartz, Laureates: Leon Lederman, Melvin thereby discoveringthemuonneutrino at are least two types of neutrinos, Nobel work:showingthatthere Nobel awarded:1979 Discovery made:1960s Abdus Salam,andSteven Weinberg Laureates: SheldonLee Glashow, mitted by photons) andtheweakforce(trans- electromagnetic force(transmittedby troweak theory that explains both the Nobel for:developingaunifiedelec- Nobel awarded:1968 Discovery made:1959–1964 Laureate: Luis Alvarez detection andanalysistools new of development the through achieved particles, of number Nobel work:discoveringalarge ν u For more information, visitnobelprize.org.Text: DavidHarrisandKurtRiesselmann to the development of the Standard Model, beginning with the “particle explosion” in the 1950s. explains a steadily increasing number of subatomic phenomena. Modelemerged.Ithasbroughtordertotheparticlezooand patterns. SlowlytheStandard experiments. By morethan100particleswereknownandphysicistsbegantofind 1960, The 1950s saw a proliferation of particle discoveries, thanks to the advent of accelerator-based γ s t μ Here is a brief summary of15 Here isabrief summary W b d W and predicting the bottom predicting that the the that predicting Z s Z bosons)

tral Nobel work:discoveringthatneu- 1980 Nobel awarded:1980 Discovery made:1964 Val Fitch Laureates: JamesCroninand known asCP matter-antimatter symmetry strange quark,violatethefundamental 1995 Nobel awarded:1995 Discovery made:1956 (sharing theprizewithMartinPerl) Laureate: Frederick Reines neutrino Nobel work: Nobel awarded:1969 1964 Discovery made:1953,1961, Laureate: MurrayGell-Mann of strangeness andquarks by introducingtheconcepts zoo particle observed experimentally the Nobel work:classifying 1999 Nobel awarded:1999 Discovery made:1971 Martinus Veltman Laureates: Gerardus‘tHooftand structure oftheelectroweaktheory foundation, elucidating the quantum on afirmermathematical ics theory Nobel work: placing particle phys- Nobel awarded:1995 Discovery made:1976 prize withFrederick Reines) Laureate: MartinPerl (sharingthe particles generation ofelementary third the to belongs that cle lepton, the first observation of a parti Nobel work: discovering the tau W ν u τ s Nobel Prize-winning discoveries e K mesons, which contain a mesons,which contain Z d detecting thefirst 31 s

-

Nobel awarded:1976 Discovery made:1974 Samuel Ting Laureates: Burton Richter and inexperiments fourth quarkobserved discovery of the charm quark, the Nobel work: Nobel awarded:2002 Discovery made:1980s prize withRiccardoGiacconi) Masatoshi Koshiba (sharingthe and Davis Raymond Laureates: ing thefieldofneutrinoastronomy - by supernovaexplosions, thusstart and sun the by produced neutrinos, Nobel work: Nobel awarded:2004 Discovery made:1973 Politzer, andFrank Wilczek Laureates: DavidGross, ated bytheexchange ofgluons. due tothestrongnuclearforce,medi- together they remaintightlybound quarks move away from each other 1984 Nobel awarded:1984 Discovery made: 1983 Simon vanderMeer Laureates: CarloRubbiaand Nobel work: first direct observation ofthe first directobservation the to led that project the to Nobel work:makingcontributions Nobel awarded:1990 Discovery made:1968 Kendall,Henry andRichard Taylor Laureates: JeromeFriedman, blocks: quarks building smaller of made are evidence thatprotonsandneutrons first the Nobel work:finding Z W bosons ν u g c e closely connected closelyconnected Z d discovering that as two discovering thatastwo detecting cosmic pioneering work in the pioneering workinthe W

and

symmetry | volume 06 | issue 02 | may 09