Microcosmos. Elementary Particle Physics. I. Quantum world II. CERN: past & present III. Particle physics matters! IV. Astroparticle physics

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1 Elementary Particle Physics Microcosmos I. Quantum world II. CERN: past & present III. Particle physics matters! IV. Astroparticle physics Frank Linde Nikhef & UvA

2 Dark ages

3 Long ago Empedocles Plato Aristoteles Leucippus Democritus Air Wate Fire Earth

4 Alchemy Lead Gold

5 Water electrolysis

6 Number of atoms per volume independent of atom type! (Avogadro) N A atoms = 1 Mole 22.4 liters Atoms N A = /Mol How large? meters How heavy? kilograms How many? /gram hydrogen 6

7 Question How many atoms of Ceasar s last blast do you think you inhale whenever you take in air? A. between and 1000 B. less than C. more than 1000

8 Periodic Het Periodiek Table Systeem of Elements nummering: kernlading Nobel gasses Not part of the original Mendeleev periodic table

9 The atom

10 Thomson 1897

11 Thomson 1897 e/m = C/kg

12 q e = C m e = kg Millikan 1900

13 electron

14 Atoms: Thomson s view

15 Atoms: Rutherford s view

16 Elementary particles (1932): Electron, Proton & Neutron 1897 electron Thomson 1911 nucleus Rutherford 1911 proton Rutherford 1932 neutron Chadwick

17 Physics just before 1900??????? all ok??????? Done? No: few minor problems: black body radiation no eather? natural radioactivity (Curie et al.) stability of the Rutherford atom

18 I. Special relativity 1905

23 Intermezzo: Einstein & relativity Time travel becomes a reality!

24 click of the light clock at rest: t hence-and-forward light flash period t: L t = 2L c c= m/s (exact) observer at rest

25 c= m/s (exact) click of the moving light clock: t hence-and-forward light flash period: t v [m/s] L t = 2 L2 +(½vt ) 2 c (ct ) 2 = 4L 2 +(vt ) 2 t = 2L = c 2 -v 2 t 1-v 2 /c 2 t ½vt vt Moving clock clicks slower! observer moving with velocity v

26 II. Quantum world

27 Imagination

28 Light: quantum effects Planck 1900 Einstein 1905 Compton 1922 Planck ( ) Einstein ( ) Compton ( )

29 I. Black body radiation Planck 1900

30 Stacking waves! Fit ½, 1, 1½, 2, etc. wavelengths in box such that amplitude=0 on walls L Easier to fit short wavelengths! λ=2 L λ=1 L λ=½ L

31 Light wave's energy: classical E continuous! energy amplitude 2

32 Radiated energie spectrum: classical energy density ultra-violet catastrophe 8π λ = 1 kt E λ ρ 4 0 µm 0,5 µm wavelength (λ)

33 Light wave's energy: quantum E = N hf Planck s constant h = J/s energy E discrete! # quanta N E = 5 hf E = 4 hf E = 3 hf E = 2 hf E = hf

34 Radiated energy spectrum: quantum energy density 8π 1 ρ λ = E 4 hc λkt λ e 1 hc λ 0 µm 0,5 µm wavelength (λ)

35 Color T=2,500 o C the sun T=5,000 o C T=7,500 o C T=10,000 o C T=12,500 o C T=15,000 o C

36 Universe as black body radiator T K o C

37 Big Bang s afterglow on your TV

38 II. Photo electric effect incident light wavelength λ (frequency f) knocked out electrons Einstein 1905 slab of material

39 Photo-electric effect

40 III. Compton effect scattered light wavelength λ incident light wavelength λ scattered electron Compton 1922

41 Duality: wave & particle characteristics It is safe to say that nobody understands quantum mechanics. R.P. Feynman

42 Quantum mechanics is magic. Daniel Greenberger. Everything we call real is made of things that cannot be regarded as real. Niels Bohr. Those who are not shocked when they first come across quantum theory cannot possibly have understood it. Niels Bohr. If you are not confused by quantum mechanics, you do not understand it. John Wheeler. If quantum theory is correct, it signifies the end of physics as a science. more Albert Einstein. I do not like quantum mechanics; I am sorry I ever had anything to do with it. Erwin Schrödinger. quotes

43 Atom: quantum effects Bohr 1910 Heisenberg 1925 Schrödinger 1927 Bohr ( ) Heisenberg ( ) Schrödinger ( )

44 Bohr s atom model 13.6 = n En 2 ev n = n=3 n=2 n=1 Balmer serie

45 µm n µm n µm n Balmer binding energy (ev) quantum number (n) Paschen Lyman ev n 13.6 E 2 n = ev

46 Heisenberg s uncertainty principle 4 /2 Δt large Δt small light t [s] Δf large Δf small light f [1/s] electron electron

47 Schrödinger s wave equation 1 H ground state n=1

48 s states n=1 n=2 n=3

49 p & d states

51 Electron: quantum details Lorentz & Zeeman 1896 Uhlenbeck & Goudsmit 1925 Pauli 1925 ( ) ( ) ( ) ( ) Leiden Amsterdam Leiden Leiden ( )

52 Stern Gerlach N Z Zeeman N Z

53 Electron spin! Uhlenbeck Goudsmit

54 Democracy: all electrons are equal Pauli: Each electron in a different state! electron = asocial

55 Perfect description of atoms!

56 The electron Mass: gram Electric charge: Coulomb Mean lifetime: (infinite) seconds Spin : ½

57 Relativistic quantum theory Dirac 1928 Anderson 1932 Feynman 1947 Dirac ( ) Anderson ( ) Feynman ( )

58 Dirac s anti-matter hypothesis negative energy positive energy γ γ e + e - e - e + e - e +

59 Anderson s anti-electron discovery γ e + e -

60 Positron EmissionTomograph

61 Angels & Demons: the movie

62 Feynman: fabulous accuracy Z N e - e - Z N Feynman 1947 Experiment: µ e = eh/(4πm e ) Theory: µ e = eh/(4πm e )

63 Precession

64 home

65 Precession µ µ = eh/(4πm µ ) # of events 100 µs 200 µs 300 µs 400 µs 500 µs 600 µs 700 µs time in µs

66 Real fun: creation & annihilition Compton scattering: γe - γe - Möller scattering: e - e - e - e - Bhabha scattering: e + e - e + e - the only interaction time Pair creation: γγ e + e - Pair annihilation: e + e - γγ

67 Particle collisions

68 boring collisions

69 exciting collisions

70 high energy fun collisions E=mc 2 large mass

71 Elementary Particle Physics Microcosmos I. Quantum world II. CERN: past & present III. Particle physics matters! IV. Astroparticle physics Frank Linde Nikhef & UvA

3.01 Understanding Atoms

3.01 Understanding Atoms The Events Leading to the Discovery of the Building Block of Matter Dr. Fred Omega Garces Chemistry 111 Miramar College 1 3.02 Atomic Evolution Environmental Problems in our Lifetime