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Die Entdeckung des t Lepton

Die Entdeckung des t Lepton. Nobelpreis 1995: Martin L. Perl. Veröffentlichung (1975). Literatur. Reflections on the Discovery of the Tau Lepton, M.L. Perl, Nobel Lecture (1995)

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Die Entdeckung des t Lepton

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  1. Die Entdeckung des t Lepton Nobelpreis 1995: Martin L. Perl

  2. Veröffentlichung (1975)

  3. Literatur • Reflections on the Discovery of the Tau Lepton, M.L. Perl, Nobel Lecture (1995) • Evidence for Anomalous Lepton Production in e+e- Annihilation, M.L.Perl et al., Phys. Rev. Letters 35 (1975) 1489 • Review of t Lepton Properties, G.L.Feldman, SLAC-PUP-2230 (1978)

  4. Inhalt der Vorlesung • Status der Hochenergiephysik um 1975 • Warum Suche nach (schweren) Leptonen? • Experimentelle Methoden • Detektor und Meßmethode • Das neue Teilchen U (=unknown) • Zerfall und Nachweis • Bestätigung des t • Zusammenfassung und Ausblick

  5. Warum e+e- Collider? • e+e-: Wechelwirkung berechenbar • Collider: Energie = Masse • Warum Large Hadron Collider?

  6. e+e- Collider weltweit

  7. e+e- Collider weltweit

  8. e+e- Collider weltweit

  9. Detektor: Mark I am SLAC

  10. Feldman et al, 1977 Mark I @ SPEAR • Detectors cover polar angles 50°  q  130°, and all azimuthal angles. • 4kG field applied for momentum analysis. • Particles produced pass through: • Inner trigger counters (3mm scintillators), to eliminate the cosmic ray background. • 4 sets of spark chambers. • Outer trigger counters (25mm scintillators), to measure the time of flight. • A 9cm Al coil (24g cm-2). • An array of lead-scintillator shower counters (160g cm-2: 5 radiation lengths).

  11. Mark I @ SPEAR • A 20cm Fe yoke (160g cm-2), which filters hadrons. • 2 sets of spark chambers. • Interspersed slabs of barite loaded concrete (222g cm-2) and spark chambers, to detect muons only. • To reach level 2, a particle must pass through 65cm of Fe (equivalent), and possess p = 910 MeV c-1.

  12. e-m Ereignis

  13. Ergeinisse nach cuts

  14. Correlationen

  15. Schlußfolgerung von Perl et al.

  16. 2- oder 3-Körperzerfall? 3-Körperzerfall 2-Körperzerfall

  17. Masse?

  18. Masse im Detail

  19. Anteil der leptonischen Zerfälle

  20. Spin?

  21. Lebensdauer?

  22. The Generations of Matter • Note that both quarks and leptons exist in three distinct sets. • Each set of quark and lepton charge types is called a generation of matter (charges +2/3, -1/3, 0, and -1 as you go down each generation). • The generations are organized by increasing mass. • All visible matter in the universe is made from the first generation of matter particles -- up quarks, down quarks, and electrons. • This is because all second and third generation particles are unstable and quickly decay into stable first generation particles.

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