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Particle Physics

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Beginning of Nuclear Substructure

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The Particle Zoo

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Classification

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Conservation Laws

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π γ γ π γ

γ γ γ

0 0→ →

→ →+ − + −

but not

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p

B

+ →+ =

+ ++π ∆: 1 0 1

µ ν ν µ

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= − += + +

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1 0 0 1

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Lifetime of Particles

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∆++ +→ +p π

t =×

= ×−

−103 10

1524 m

3 10 m / s s8

π γ γ0 →

K K+ + + − + +→ → +π π π µ ν µ

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Strangeness

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K+ + + −→ π π π

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The “Eightfold Way’’

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Periodic table for “elementary particles”!

Isospin

Charge

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Quarks

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Rutherford Scattering

Experiments by Geiger & Marsden in 1909

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Rutherford Model of the Atom

Conclusion: the atom contains a positive nucleus < 10 fm in size (1 fm = 10-15 m)

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How we “see” particles

The smaller the wavelength, the smaller the features observed.

Recall that the deBoglie wavelength of a particle is λ = h / p

So we need high energies to probe quarks

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Particle Accelerators

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Size of Nuclei

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proton

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Deep Inelastic Scattering

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Quarks within the Proton

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Proton is a Complicated Object

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November Revolution

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The Bottom Quark

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Discovery of the top quark

The top quark was discovered in 1995 with a mass of 175 GeV, as much as an atom of gold!

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CDF and DØ

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Particle Physics Detectors

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History of the Discovery of Quarks■ 6/$&� ����

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The Standard Model of Particle Physics

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Jets

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quark

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π

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Where’s the Glue?

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Do Quarks have Substructure?

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European Center for Nuclear Research (CERN)

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CERN Particle Accelerators

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