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atom

Elementary particles. Key dates 1808 Dalton's Plum Pudding model. 1897 Thomson's electron discovery. 1910 Rutherford's scattering of α particles with Geiger & Marsden, Manchester. 1913 Bohr theory of the atom. 1919 Rutherford – discovery of proton. 1930 Dirac predicts positron.

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atom

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  1. Elementary particles Key dates 1808 Dalton's Plum Pudding model. 1897 Thomson's electron discovery. 1910 Rutherford's scattering of α particles with Geiger & Marsden, Manchester. 1913 Bohr theory of the atom. 1919 Rutherford – discovery of proton. 1930 Dirac predicts positron. 1931 Pauli predicts neutrino. 1932 Fermi names predicted neutrino. 1932 Anderson observes positron. 1932 Chadwick – discovery of neutron. 1955 Segre & Chamberlain – observed anti-proton. 1956 Neutrino observed. 1960 Salam & Weinberg predicted W & Z bosons. 1975 Perl – discovery of Tau 1784MeV/c². 1983 CERN W & Z bosons observed. ???? Higgs Boson (not quite yet). Forces: 1. strong (hadronic) nuclear interaction (carried by exchange bosons called gluons). 2. electromagnetic interaction (carried by exchange particle photon). 3. weak nuclear interaction (carried by W & Z exchange bosons). 4. gravitational interaction (carried by predicted graviton exchange boson). atom Hadrons Strong, 'hadronic' interactions (made of quarks 'up', 'down' & 'strange' (flavors) 'top', 'bottom' & 'charm' (newer).) Leptons Spin ½ 's …so 'fermions'. Weak interactions. Fundamental particles. No size. Mostly light. Each has an anti-particle. Baryons Spin ½ 's …so 'fermions'. Heavy hadrons. Triplets of quarks. Mesons Spin 0,1,2,..so 'bosons'.. Intermediate mass. Quark & anti-quark. Muon νμ Neutrino Tau τ (heavy) Electron e Muon μ Nucleons Others Electron neutrino νe Tau neutrino ντ Neutron udd Proton uud Quarks Fundamental particles. Up, down, strange, top, bottom, charm Lambda uds Sigma Xi Pion ud Kaon Eta

  2. Conservation laws Apparatus: Cloud chambers Bubble chambers Charge Electrostatic charge Properties conserved during reactions and decays of elementary particles: Charge Energy Angular momentum Linear momentum Lepton number Baryon number Strangeness (not Universal) Fermions? Pauli exclusion? Strangeness discovered Gellman & Nishijima (1952).

  3. Field particles Quantum dynamics: Virtual photons (quantum electrodynamics) Graviton (gravitational interaction) Vector boson (weak interactions) Gluon (strong interactions between quarks) The Standard Model Including: Quark model Electroweak theory Quantum chromodynamics Feynman Diagrams

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