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Outline lecture (HL-1) Particle Production

Outline lecture (HL-1) Particle Production. Particle production in e + e - collisions Detection techniques Lepton pair production Resonances Non-resonant hadron production Gluon emission, jets Literature: Povh/Rith chapter 9 (particle production)

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Outline lecture (HL-1) Particle Production

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  1. Outline lecture (HL-1)Particle Production • Particle production in e+e- collisions • Detection techniques • Lepton pair production • Resonances • Non-resonant hadron production • Gluon emission, jets • Literature: Povh/Rith chapter 9 (particle production) • Burcham/Jobes Chapter 2 (exp. techniques) Kernfysica: quarks, nucleonen en kernen

  2. particle production in e+e- collisions electromagnetic and weak processes space timemomentum Z0 Kernfysica: quarks, nucleonen en kernen

  3. Kernfysica: quarks, nucleonen en kernen

  4. L3 detector at LEP Kernfysica: quarks, nucleonen en kernen

  5. 2-jet event in ALEPH detector at LEP Kernfysica: quarks, nucleonen en kernen

  6. excursion to planned experiments at GSI Darmstadt (D)detector for 1.5 – 15 GeV/c reactions full solid angle, excellent energy and angle resolution for , K,  Kernfysica: quarks, nucleonen en kernen

  7. Simulated event in “Straw Tube Tracker” gas discharge in 5 mm  straws from Al-mylar foil, 26 m walls, 20 m sense wires (ca. 3 kV /cm) Kernfysica: quarks, nucleonen en kernen

  8. “oldfashioned” scintillator detectors with modern crystals and advanced photodiode readout Flash ADC Kernfysica: quarks, nucleonen en kernen

  9. from leptons to heavy quarks Kernfysica: quarks, nucleonen en kernen

  10. what is the mass of the  ?  lepton threshold production sharp increase of production ratio due to pair production Kernfysica: quarks, nucleonen en kernen

  11. e+ e- annihilation cross section pointlike (re <10-3 fm) spin=1/2 fermions f, Q2=s=4E2 with Nc colors, charge ezf, CM velocity , mfc2<<E 2 × × e ez E s d f = + J + - b J 2 2 2 N ( 1 cos ( 1 ) sin ) c + W 2 4 d Q m2 c f a 2 = + J + - b J 2 2 2 2 2 N z ( c ) ( 1 cos ( 1 ) sin ) h c f 4 s Kernfysica: quarks, nucleonen en kernen

  12. e+ e- annihilation measurement QED prediction lepton universality Kernfysica: quarks, nucleonen en kernen

  13. + - e- e+ hadronic states coupling to photon (JP=1-) e+, + -, e- e+e- scattering e- e+ interference e- e+ dominant process for e+e- production e- e+ intermediate hadron state timelike process spacelike process interference analysis for + - spin-parity analysis of resonances Kernfysica: quarks, nucleonen en kernen

  14. hadron resonances J/ production Breit-Wigner resonance cross section h low energy resonances ( , , ): 4    150 MeV typical hadronic lifetimes:  interpreted as bound states (JP=1-) e J/ resonance: e== 4.8 keV, h = 59 keV (lepton universality)  = 69 keV Kernfysica: quarks, nucleonen en kernen

  15. non-resonant hadron production primary qf looses energy by secondary formation: hadronisation process (1fm/c) hadron jets primary production for f flavours, Nc colours: Kernfysica: quarks, nucleonen en kernen

  16. evidence for 6 quark flavours hadron production ratio R must increase when passing f threshold Kernfysica: quarks, nucleonen en kernen

  17. hadron 3-jets: existence of gluons besides 2-jets from hadronisation: higher order processes 3-jet rate decreases with s=Q2 because of running of S Kernfysica: quarks, nucleonen en kernen

  18. Summary lecture (HL-1) • Particle production in e+e- collisions •  discovery • lepton universality • photon-hadron coupling • hadron resonances • quark flavours • existence of gluons • Literature: Povh/Rith chapter 9 (particle production) • Burcham/Jobes Chapter 2 (exp. techniques) Kernfysica: quarks, nucleonen en kernen

  19. Outline lecture (HL-1b)Weak Interaction • Particle production in e+e- collisions • Lepton pair production • Resonances • Non-resonant hadron production • Gluon emission, jets • Phenomenology of the weak interaction • Lepton families • Types of weak interaction • Coupling strength of charged current • Quark families • Parity violation • Literature: Povh/Rith chapter 10 Kernfysica: quarks, nucleonen en kernen

  20. Weak Interaction nuclear  decay short-range interaction heavy gauge bosons: m(W) = 80.4 GeV/c2, m(Z0) = 91.2 GeV/c2 P (parity) violation, CP (charge conjugation & parity) violation: lepton number conservation why 3 families? why mass hierarchy? CKM quark mixing matrix Kernfysica: quarks, nucleonen en kernen

  21. parity violation in nuclear  decay because  yield depends on spin orientation of nucleus: key experiment on 60Co (Mme. Wu , 1958) helicity h changes under P operation: Kernfysica: quarks, nucleonen en kernen

  22. W- 0 - n p W- W-   types of weak interactions leptonic semi-leptonic non-leptonic charged-current interactions W W- non-leptonic decays of strange hadrons: Kernfysica: quarks, nucleonen en kernen

  23. W- coupling strength (weak charge g) W boson couples to weak charge g: transition matrix element: very short-range interaction:  point interaction (Fermi Ansatz) strength  GF (Fermi constant) convenient definition: GFto be determined from  decay width: g g Kernfysica: quarks, nucleonen en kernen

  24. universality of weak interaction  decay width and lifetime: (if universal) Kernfysica: quarks, nucleonen en kernen

  25. W- W- g g sinC g g cosC u u d s weak charge universality weak coupling to quarks from semi-leptonic hadron decays: GFappears 4% smaller GFappears X20 smaller Cabibbo’s mixing hypothesis (1963), now in quark picture: mixing of partner flavour eigenstates, Cabibbo angle C for 2 families W+ W- sinC  0.22 exp. from semi-leptonic or hadronic decays: Kernfysica: quarks, nucleonen en kernen

  26. Change of decay rates by Cabibbo angle transition ratio Kernfysica: quarks, nucleonen en kernen

  27. W q Cabibbo-Kobayashi-Maskawa (CKM) matrix generalization to 3 quark families q’ gVqq’ Vqq’ correlated through unitarity: unitary triangle  3 real mixing angles, 1 phase factor (KM phase)  = f(123) KM phase to be determined from CP violation in B-decays (b  u) Kernfysica: quarks, nucleonen en kernen

  28. - s = -1/2 J=0 s = 1/2 helicity suppressed  decay semi-leptonic weak decay of - why so strong? (phase space  3.5 times larger!) h = +1 (?) h = +1 (!) h = +1 forbidden for lefthanded massless leptons! helicity only lorentzinvariant for massless particles : with mass: lefthanded component 1-  2.6 10-5 for e  0.72 for  Kernfysica: quarks, nucleonen en kernen

  29. Summary lecture (HL-1b) • Particle production in e+e- collisions •  discovery • lepton universality • photon-hadron coupling • hadron resonances • quark flavours • existence of gluons • Phenomenology of the weak interaction • parity violation • weak charge universality • quark mixing matrix Kernfysica: quarks, nucleonen en kernen

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