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HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen1 Outline lecture (HL-1) Particle Production Particle production in e + e - collisions Detection.

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Presentation on theme: "HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen1 Outline lecture (HL-1) Particle Production Particle production in e + e - collisions Detection."— Presentation transcript:

1 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen1 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)

2 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen2 particle production in e + e - collisions electromagnetic and weak processes space time momentum  Z0Z0

3 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen3

4 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen4 L3 detector at LEP

5 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen5 2-jet event in ALEPH detector at LEP

6 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen6 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, 

7 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen7 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)

8 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen8 “oldfashioned” scintillator detectors with modern crystals and advanced photodiode readout Flash ADC

9 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen9 from leptons to heavy quarks

10 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen10  lepton threshold production sharp increase of production ratio due to  pair production what is the mass of the  ?

11 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen11 e + e - annihilation cross section pointlike (r e <10 -3 fm) spin=1/2 fermions f, Q 2 =s=4E 2 with N c colors, charge ez f, CM velocity , m f c 2 <

12 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen12 e + e - annihilation measurement lepton universality QED prediction

13 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen13 hadronic states coupling to photon (J P =1 - ) e+, +e+, +  -, e - ++ -- e-e- e+e+ e+e+ e-e- e-e- e+e+ e-e- e+e+ intermediate hadron state timelike processspacelike process interference e + e - scattering dominant process for e + e - production interference analysis for  +  - spin-parity analysis of resonances

14 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen14 hadron resonances J/  production Breit-Wigner resonance cross section low energy resonances ( , ,  ): 4    150 MeV typical hadronic lifetimes: interpreted as bound states (J P =1 - ) J/  resonance:  e =   = 4.8 keV,  h = 59 keV (lepton universality)  = 69 keV ee  hh

15 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen15 non-resonant hadron production primary q f looses energy by secondary formation: hadronisation process (  1fm/c) hadron jets primary production for f flavours, N c colours:

16 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen16 evidence for 6 quark flavours hadron production ratio R must increase when passing f threshold

17 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen17 hadron 3-jets: existence of gluons besides 2-jets from hadronisation: higher order processes 3-jet rate decreases with s=Q 2 because of running of  S

18 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen18 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)

19 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen19 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

20 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen20 Weak Interaction nuclear  decay short-range interaction heavy gauge bosons: m(W  ) = 80.4 GeV/c 2, m(Z 0 ) = 91.2 GeV/c 2 P (parity) violation, CP (charge conjugation & parity) violation: lepton number conservation why 3 families? why mass hierarchy? CKM quark mixing matrix

21 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen21 parity violation in nuclear  decay because  yield depends on spin orientation of nucleus: key experiment on 60 Co (Mme. Wu, 1958) helicity h changes under P operation:

22 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen22 types of weak interactions W-W- W-W- WW leptonic semi-leptonic non-leptonic charged-current interactions non-leptonic decays of strange hadrons: W-W- n  00 W-W- p  --

23 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen23 coupling strength (weak charge g ) W boson couples to weak charge g: transition matrix element: very short-range interaction:  point interaction (Fermi Ansatz) strength  G F (Fermi constant) convenient definition: G F to be determined from  decay width: W-W- g g

24 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen24 universality of weak interaction  decay width and lifetime: (if universal)

25 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen25 weak charge universality weak coupling to quarks from semi-leptonic hadron decays: G F appears 4% smaller G F appears X20 smaller W-W- g  g cos  C d u W-W- g  g sin  C s u Cabibbo’s mixing hypothesis (1963), now in quark picture: W+W+ W-W- mixing of partner flavour eigenstates, Cabibbo angle  C for 2 families exp. from semi-leptonic or hadronic decays: sin  C  0.22

26 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen26 Change of decay rates by Cabibbo angle transition ratio

27 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen27 Cabibbo-Kobayashi-Maskawa (CKM) matrix generalization to 3 quark families W q q’ g  V qq’ V qq’ 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)

28 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen28 helicity suppressed  decay semi-leptonic weak decay of  - (phase space  3.5 times larger!) -- J=0s = 1/2s = -1/2 h = +1 (?) h = +1 (!) h = +1 forbidden for lefthanded massless leptons! helicity only lorentzinvariant for massless particles : with mass: lefthanded component  1-   for e  0.72 for  why so strong?

29 HL-1 May 2, 2006Kernfysica: quarks, nucleonen en kernen29 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


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