The Size of Small Things

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The Size of Small Things
A History of Particle Physics from Molecules to
Quarks, and the Birth of Modern Physics
Dennis P. Weygand Thomas Jefferson National
Accelerator Facility Newport News, Virginia
450 BC Leucippus Atomic View of
Matter 400 BC Democritus (student of
Leucippus) The only existing things
are the atoms and empty space all else
is mere opinion.
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The Atomic View Avogadro's Hypothesis (1811)
At the same T and P, equal volumes of gas
contain equal numbers of molecules
Boyle's Law (1662)
Charles' Law (1802)
Dalton's Law (1801)
Gay-Lussac's Law (1808)
Gases react in proportion of simple integers
The modern kinetic molecular theory of gases
essentially started with Bernoulli's suggestion
in 1734 that the pressure exerted by a gas on the
walls of its container is the sum of the many
collisions by individual molecules, all moving
independently of each other.
Ideal Gas Law
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Robert Brown 1827
The Atomic View
Einstein 1921
In this paper it will be shown that,
according to the molecular-kinetic
theory of heat, bodies of a
microscopically visible size suspended in liquids
must, as a result of thermal molecular
motions, perform motions of such
magnitudes that they can be easily
observed with a microscope. It is possible that
the motions to be discussed here are
identical with so-called Brownian
molecular motion however, the data
available to me on the latter are so imprecise
that I could not form a judgment on the
question. (John Stachel, ed.,
Einstein's Miraculous Year Five papers
that changed the face of physics, Princeton
University Press, 1998, 85 Einstein's
original papers are included in the
Collected Papers of Albert Einstein, vol. 2)
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The Periodic Table
Mendeelev and Meyer (1869)
Mendeelev' Original Draft Periodic Table
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Joseph Loschmidt 1865
The Size of Molecules (s)
Mean Free Path
Rudolph Clausius
Maxwell
Maxwell (1860) l 62 nm
Meyer l 140 nm
Coefficient of Condensation
Lofschmidt
For air
the appropriate unit of length is a millionth of
a millimeter
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Jean Perrin (1908)
Perrin 1926
Avogadro's Number (N0)
number density
suspensions of gamboge and mastic
Law of Atmospheres
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Blackbody Radiation
Nobel Prize Rayleigh 1904 Planck 1918
Rayleigh-Jeans Law (classical) (1900)
Planck's Law (1900)
Standing waves of EM radiation confined in a box
Assume discrete energy u
(Boltzmann)
Spectral Distribution Function
Corresponding Energy
Mean oscillator energy
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Rutherford Scattering (1911-1913) Geiger-Marsden
Rutherford (Chemistry) 1909
Coulombs Law
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Anders Angstrom (1853) Gustav Kirchoff Robert
Bunsen (1860)
Energy Levels of the Hydrogen Atom
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The Hydrogen Atom
Balmer Series (1884)
Rydberg (1890)
Paschen (1908)
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The Bohr Atom (1913)
Bohr 1922
Bohr's First Postulate
Bohr Radius
0.53 Angstroms
Bohr's Second Postulate
Rutherford Atom
electrons only radiate when changing states
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Maxwell's Equations (1873)
Coulomb's Law (1791)
Faraday's Induction Law (1830)
Lorentz condition
Wave Equation
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Michelson-Morley Experiment (1879)
Michelson 1907
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Probability Density (1924)
Pauli 1945 Born 1954
The Pauli Exclusion Principle (1925)
Max Born
Probabilty Amplitude
Probabilty Density
Wolfgang Pauli
No two electrons can occupy the same quantum state
Bosons (integer spin) Fermion
(half-integer spin) -
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Dirac 1927
A Modern Physics View of Force
Tomonaga, Schwinger, Feynman 1965
P.A.M. Dirac
J. Schwinger
F. Dyson
R. Feynman
S-I Tomonaga
Fine structure constant
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p-meson (1935,1947)
Yukawa 1949 Powell 1950
Yukawa Particle (Lattes, Muirhead,Occhialini,Po
well,Wills)
Yukawa Lattes
Nature 159, 694-697 (1947)
Mount Chacaltaya (Bolivia)
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Effective Mass and the Uncertainty Principle
Heisenberg 1932
Heisenberg Uncertainty Principle
1
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Breit-Wigner Resonance Formula
Wigner 1963
For an unstable particle
where
phase
yy
Mass (GeV/c2)
Mass (GeV/c2)
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Cyclotron (1929)
Lawrence 1939
First Cyclotron
27 (1932)
11 (1931)
BNL AGS
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First Nucleon-Pion Resonance D (1952)
Fermi 1938 Lederman, Steinberger (1988)
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Luis Alvarez Bevatron LBL
Alvarez 1968
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r meson (1961)
Cosmotron BNL 1952
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Brookhaven 80 inch Bubble Chamber
Glaser 1960
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LBL/Bevatron 72 Bubble Chamber (June, 1962)
X(1530)
BNL/AGS 20 Bubble Chamber (July, 1962)
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Baryon Decuplet (1964)
Gell-Mann 1969
Samios
Gell-Mann
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Quarks, Gluons, and Color SU(3)
u d
s I,Iz 1/2 1/2 1/2 -1/2 0 Q
2/3 -1/3 -1/3 S
0 0 -1
Gell-Mann 'quarks'
Zweig 'aces'
Quantum Chromodynamics SU(3) Gauge Theory
Quantum Electrodynamics U(1) Gauge Theory
8 Coloured Gluons
1 neutral photon
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Deep Inelastic ep Scattering (SLAC/1969)
Friedman, Kendall, Taylor 1990
J. Friedman
H. Kendall
R. Taylor
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J/y November, 1974
(BNL and SLAC)
Richter and Ting 1976
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The Discovery of the Gluon (DESY 1979)
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The Quark Model Quantum Chromodynamics
The
Potential
Bali (2001)
Baryons Mesons
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The Standard Model
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Brookhaven Multi-Particle Spectrometer (MPS)
1974-1998 Exotic Mesons 1997
Charpak 1992
G. Charpak
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Continuous Electron Beam Accelerator Facility
Jefferson Laboratory
1 km
240 m
3/4 mile equivalent
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CEBAF Large Acceptance Spectrometer (CLAS)
1997-present
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all things are made of atoms R.
Feynman
The End
Thank you for your attention D.P. Weygand