基本粒子

2 The Periodic Table Mendeleev (1869) introduced the periodic table

Discovery of Electron J.J. Thomson found that Cathode rays are electrons A 陽極 O 陰極 O’ 狹縫 CC’ 平行面板 B E C C’ 圖一 Pluecher (Germany) found cathode rays in s Crookes (British) studied this extensively ·all metals ·-charge turn in magnetic field Like X-rays (Hertz, etc.) ·unaffected by e-field · can penetrate Al foil 3

4 The Structure of Atoms Rutherford (1912) showed that atoms contain a central nucleus Electrons orbit nucleus with well-defined energy and ill-defined positions m

5 The Structure of Nuclei Nucleus contains protons with charge +e and uncharged neutrons m J. Chadwick (1932) discovered neutron 2 α Be 9  6 C n 1

m The Structure of Nucleons Neutrons and protons contain quarks “Seen” in the deep inelatstic ep scattering at SLAC (1967)

7 The Constituents of Matter Protons contain uud - charge = +e Neutrons contain udd - charge = 0 quarks electron 2323 e e - -e charge u de

8 Proton Decay? tons pure water τ p >10 35 years (Experiment) τ p ~10 36 years (GUT theory) Super- Kamiokande experiment is 1,000 m underground in Mozumi Mine photomultiplier tubes Cherenkov radiation

9 Prediction of Antimatter Paul Dirac predicted existence of the positron in 1928 Dirac’s equation implies: positron mass = electron mass positron charge = +e

10 Discovery of Antimatter Anderson (1932) discovered the positron predicted by Dirac

11 Production of e + e - Pairs High energy  -ray becomes an electron-positron pair e + e - E = mc 2

12 Antimatter Disappears in a Matter Dominant World e + e - Inverse process also occurs, electrons and positrons annihilate to produce photons (energy) E = mc 2

13 The Fundamental Particles u d tc sb six quarks e     e six leptons Along with their anti-particle partners Spin ½ fermions

14 Basic Interactions

15 A Colorless World Quarks Leptons uct dsb Charge=+2/3 Charge=-1/3 π Meson Λ Baryon Mesons: π,ρ,Φ,k,B… Baryons: p,n,Λ,Σ,Δ… e μ τ ν μ ν e ν τ Neutrinos Charge=0 Charge=-1 Mediator γ G Z0Z0 W ± ? graviton

2005/12/9 物理光耀世界 ( Ⅱ )- 紀念 1905 物理奇蹟年的一百週年 16 Evolution of the Universe The Universe began with a “Big Bang” about 15 billion years ago -270 o ? heavy elements formed in stars stars and galaxies exist, atoms form neutrons quark "soup" 15 billion years 1 million years 1 second deg 10 deg 10 9 deg 6000 o -255 o 3 minutes helium nuclei formed microwave background radiation fills universe 300,000 years 4000 o life on earth, molecules form dominates matter and protons formed 1 billion years s Big Bang

17 Discovery of Parity Violation C.S. WU Co 60 B field e- e Madame Wu measured the asymmetry in the beta decay rate of Co 60 and found parity was maximally violated In 1957