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Elementary Particles Chapter 14

Elementary Particles Chapter 14. ~ Harris Chapter 11; Rohlf: “Modern Physics from a to Z o ” www.pdg.lbl.gov Particle Adventure at http://pdg.lbl.gov/2005/html/outreach.html. Outline. Fundamental Objects 14.1, 14.3, 14.5 Fundamental Interactions 14.2

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Elementary Particles Chapter 14

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  1. Elementary ParticlesChapter 14 ~ Harris Chapter 11; Rohlf: “Modern Physics from a to Zo” www.pdg.lbl.gov Particle Adventure at http://pdg.lbl.gov/2005/html/outreach.html

  2. Outline • Fundamental Objects 14.1, 14.3, 14.5 • Fundamental Interactions 14.2 • Odd Topics & Strange Goings-On 14.7

  3. Fundamental Objects 3 generations 3 families 6 flavors leptons 3 generations 3 families 6 flavors quarks all spin ½ objects 0.511 MeV < 2 eV 105 MeV < 0.17 MeV 1784 MeV < 18.2 MeV ~350 MeV ~700 MeV 1500 MeV ~500 MeV 174000 MeV 4700 MeV

  4. Fundamental Objects 3 generations 3 families 6 flavors leptons 3 generations 3 families 6 flavors quarks Binding energy is a major effect proton = uud = 350 + 350 + 700 = 1400 >> true mass 938 MeV

  5. Fundamental Objects 3 generations 3 families 6 flavors leptons 3 generations 3 families 6 flavors quarks all spin ½ objects Electric charge of leptons Electric charge of quarks

  6. Fundamental Objects Field particles or gauge bosons 8 gluons (graviton) --- --- < 6E-17 eV 80, 91 GeV other required objects Higgs bosons LR bosons > 114 GeV > 715 GeV

  7. Fundamental Interactions

  8. 4 Fundamental Interactions • QED – Quantum Electrodynamics • (electromagnetism) • QCD – Quantum Chromodynamics • (strong force) • QFD – Quantum Flavor Dynamics • (weak interaction) • Quantum Gravity

  9. Fundamental Interactions a = (vertex fn)2

  10. Comments on Fundamental Interactions • Range • photons are ‘stable’  DE = 0  cDt = ∞ • IVB are ‘unstable’  DE ~ 2 GeV  cDt ~ 0.1 cm • gluons – no info • Electric Charge • all quarks and e m t and W± can participate in QED • since g has no charge, g cannot interact with g ‘s. • Color • only quarks & gluons have color  participate in QCD • Since g has color, g can interact with g‘s  “glueballs” • Flavor • all quarks and leptons have “flavor”, therefore can participate in QFD

  11. Composite Objects • Hadrons • mesons – qq • baryons – qqq • quaterions – not observed • pentaquarks – i.d.i. • .

  12. QED • Stationary States • Reactions

  13. QED - Stationary States Some kind of experiment to excite the system e p

  14. Note: even though we have quessed a good potential function, we realize that we will have to include s-o, rel KE, Darwin, Lamb shift, ... -- and the perturbations could have been big.

  15. Feynmann Diagrams g e+ g e- e- e- time arrows are added to help identify particles versus antiparticles e+ e- e+ e+ g g e- e+ e- e-

  16. e- m- e+ e+ g g e- e- e+ m+ u e+ c e+ g g e- e-

  17. QCD • Stationary States • Reactions

  18. QCD - Stationary States

  19. confinement term K1 ~ 50 MeVfm K2 ~ 1000 MeV/fm ‘Coulomb’ term ? ? As a matter of fact, must have V  0 by about 1 fm.

  20. RUBBER BANDS stretch & break stretch 2 ends U = ½ k (Dx)2 4 ends QUARK PAIRS stretch & break the color field stretch

  21. How-To: quark-quark reactions meson ? meson ? spectator quarks Which pairs of quarks interacted?

  22. uG uR dR dG uR uG

  23. dR dG q = uds... uR uG Because aQCD > 1, higher order diagrams more important, can’t use perturbation theory. must use another technique to do calcs “string theory” “QCD is non-renormalizable.” (in this form)

  24. QFD • Stationary States • Reactions

  25. QFD – Stationary States need neutral & colorless system • bound system of neutrinos • not experimentally feasible • excited states of leptons • e* not observed below 90 GeV (1990) • would imply lepton compositeness  must learn about QFD from reactions

  26. e- Zo e+ QFD - Reactions Experimentally; gw = 1.7 !!! QFD is considered “weak” only because Zo, W± are massive !

  27. g e+ g e- e- e- arrows are added to help identify particles versus antiparticles e+ e- e+ e+ g g e- e+ e- e-

  28. W+ QFD – charged current d (-1/3) u W- (2/3) W- v (0) u e (2/3) (-1) d (-1/3) e W-

  29. Zo QFD – neutral current u (2/3) u Zo (2/3) e e e e+ Zo Zo

  30. QFD – “flavor changing neutral currents” Zo u (2/3) c (2/3) Zo Zo d (-1/3) s (-1/3) NOT OBSERVED – or at least very rare

  31. neutrino experiments ? ? W- d u (-1/3) (2/3)

  32. neutrino experiments e v W- e+ d u (-1/3) (2/3) W+ v only interact with neg quarks u d (2/3) (-1/3) …converse…

  33. Strange Goings-On • CPT • Parity Violation • Regeneration of the kaons • Time Reversal Violation • CKM & MNS Matrix • Quark mixing • Neutrino Mass-Mixing, a.k.a Neutrino Oscillations • Unification • Electroweak Interaction

  34. Quark MixingCKM matrixCabibbo-Kobayashi-Maskawa matrix are QCD or ‘mass’ eigenstates W- W- W- u vm ve m- e- d W- u s

  35. Quark MixingCKM matrixCabibbo-Kobayashi-Maskawa matrix http://en.wikipedia.org/wiki/Cabibbo%E2%80%93Kobayashi%E2%80%93Maskawa_matrix

  36. Quark MixingCKM matrix are QCD or ‘mass’ eigenstates In the presence of the weak interaction the states are perturbed weak eigenstates

  37. Quark MixingCKM matrix b s Weak eigenstates d probability

  38. Analogy:Coupled Pendulum Oscillators • Coupled pendulum • http://www.youtube.com/watch?v=8JhDbR7tDbg • http://www.youtube.com/watch?v=6JGTJyAQKPc http://en.wikipedia.org/wiki/Neutrino_oscillation

  39. Neutral Kaon System: Regeneration Collision regions (QCD) WI eigenstates QCD eigenstates QCD eigenstates

  40. If quark mixing, why not…?

  41. Solar Neutrino Problem MSW Effect WI eigenstates Mass eigenstates Lots of electrons vacuum 100,000 gal of cleaning fluid Search for individual Ar atoms Observed on 1/3 of what expected http://www.bnl.gov/bnlweb/raydavis/pictures.htm

  42. Neutrino Oscillations • Solar Neutrino Expts (KE ~ 1 MeV) • Homestake Mine, SD (Ray Davis) • Explanation w/i previously existing physics with proper calculation (MSW effect) • MSW effect: ve propagate through dense electrons in Sun • Atmospheric (KE ~ 1 GeV) (vacuum oscill) • Super Kamiokande • Improper ratio of vm to ve events. • Reactor Based (KE ~ 1 MeV) (vacuum oscill) • KamLAND, 53 reactors, anti-ve from fission product decay . • Event rate and energy spectrum • Energy spectrum inconsistent with ‘no oscillation’ • Accelerator Based (KE > 3 GeV) (vacuum oscill) • FermiLab vs Los Alamos • CERN & SanGrasso

  43. Neutrino OscillationsMNS matrixMaki-Nakagawa-Sakata matrix q12 ~ 34o q13< 13o q23~ 45o d = ? Mass eigenstates WI eigenstates http://www.hep.phy.cam.ac.uk/~thomson/partIIIparticles/handouts/Handout11_2010.pdf

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