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CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Lectures recorded at :

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Presentation on theme: "CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Lectures recorded at :"— Presentation transcript:

1 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Lectures recorded at : http://www.cern.ch/wlap

2 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen

3 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Can not use light microscopes to study atoms !!! Quantum mechanics tells us that particles behave like waves and visa versa:  h/p Use electron microscopes LEP the world’s biggest electron microscope electron

4 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen electron quark New Stuff from E = Mc 2 New, unstable particles, can NOT be explained as made of up and down quarks only. High Energy electron-proton scattering Jet of Particles

5 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen electron (energy U) U= 1 eV = 1.6x10 -19 J (speed at positive plate 18 000 km/s) 1 keV = 10 3 eV 1 MeV = 10 6 eV 1 GeV = 10 9 eV 1 TeV = 10 12 eV LEP = 209 GeV LHC = 14 TeV Practical Units - + 1 Volt

6 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Einstein: E = Mc 2 pc use units such that c =1 E (GeV or MeV) p (GeV/c or MeV/c) M (GeV/c 2 or MeV/c 2 ) M0c2M0c2 M proton = 0.931 GeV/c 2 ≈ 1 GeV/c 2 M electron = 0.5 MeV/c 2 ( M top = 170 GeV/c 2 ) proton diameter = length scale: 10 -15 m = 1 fermi (femtometer) E Special Relativity: ( E 2 = (pc) 2 + (M 0 c 2 ) 2 )

7 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Creating New Matter with LEP fully described by the Standard Model :

8 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Ingredients of the Standard Model To explain all matter we need three generations of quarks We also have three generations of leptons. THE COMPLETE PICTURE: Quarks Leptons charges: 2/3 -1/3 0 -1 u p d own e electron (e) c harm s trange  muon (  ) t op b ottom   tau  Two different sorts of Matter particles: -composite particles made up of quarks (called HADRONS) -non composite particles like electrons and neutrinos (LEPTONS)

9 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen u d c s t b e  e   Charge +2/3 -1/3 0 quarks (q) leptons “Fundamental” Matter Particles heavier

10 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen q q q Composite Matter Particles (hadrons) made out of quarks ( q ) and anti quarks ( q ) BaryonsMesons q q q q Anti Baryons Hundreds of possible combinations or particles hadrons

11 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Forces of Nature name of field (wave) force carrier (particle) gravitational field graviton (?) electromagnetic field (a)   (photon) weak field Z 0, W +, W - strong (color) field 8 gluons, g higgs field (*) h 0, H 0, H +, H -.. (*)Unifying the weak and the electromagnetic fields giving mass to the Z and the W’s - all other particles !!! (a) Electric and Magnetic Fields Unified by Maxwell (1864) Big Question: Can all Force Fields be unified ? (*)

12 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen the Strong Field (gluons) couple to Quarks the Weak field (W’s and Z) couple to Leptons the Electromagnetic field couple to Charge (classical: F = qE) the Gravitational field couple to Mass (Newton: F = mg) the Higgs field couple to Mass ! ! ! In fact the Higgs field is responsible for the mass ! Can detailed studies of large number of Higgs Particles give us the explanation why we have three families of quarks and leptons, and why they have such enormous mass differences ?? How the forces work LHC will tell us !

13 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen The Forces and Particles as Fields Newton and Gravity Faraday and Fields Forces as “Exchange” Particles Particles as Fields Forces and Particles as Quantum Fields Quantum Fields are part of Space itself !

14 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen How does a point in empty space know exactly the variety of particles it can produce and all their properties and their forces.... ??? Back to Heisenberg and Faraday: Particles and Forces are Quantum Fields filling every point of “Empty” Space (or the “Vacuum”). The Fields materialize as Particles when Energy is fed into this Vacuum.

15 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Heisenberg’s Uncertainty Relation: (  x)(  p) ≈ h/(2  ) or (  t)(  E) ≈ h/(2  ) (valid for the Fields as well as the Vacuum) h is Planck’s constant - a very small number, (6.6x10 -34 Js) x is position, p is momentum, t is time, and E is energy. (  x) means uncertainty in position, etc

16 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Structures are temporary, the Pattern lasts for ever ! In every Point of “Empty” Space there is full Information on all possible particles and all the fundamental forces ! Particles are produced when energy is fed into the Vacuum. Particles appear and disappear, but the “memory” remains

17 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen With LEP Blowing into the Vacuum producing the Z 0 particle Energy (e + + e - ) Collision Probability Z 0 -mass resonance curve resonance width (  E)

18 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen e-e- e+e+ e-e- e+e+ lepton anti lepton 3 jets Z 0 Decays :

19 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen 1989-1995: The 4 LEP experiments collected and studied 17 million Z particles Z particles decays “democratically” into all possible quark-anti quark pairs (sometimes accompanied by one or more gluons) and all possible lepton-anti lepton pairs. Quarks and gluons seen as jets, and charged leptons as single tracks neutrino-anti neutrino pairs are NOT observed However, the number of different neutrino species can be found from the resonance width (or lifetime) of the Z particle

20 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Z 0 resonance (line shape): E (or M) = 91.2 GeV  E (or  M) = 2.5 GeV Heisenberg: (  E) (  t) = h/2  (h = 4x10 -24 GeVs) (  t) is the lifetime  and (  E) the resonance width giving  = 10 -25 s corresponding to Only three light neutrino species, i.e. only three lepton generations, and three quark generations.

21 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Z0Z0 Lifetime of Z 0 like water in a leaking bucket: the more and bigger the holes - the shorter the lifetime a hole = a decay channel; Sizes of the holes can be calculated using the Standard Model

22 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen How many “Holes” ? Quark pairs: charge number d-d, s-s, b-b 1/3 3 (x3) u-u, c-c 2/3 2 (x3) Lepton pairs: charge number e - -e +,  - -  +,  - -  +, 1 3  e -  e,   -  , ? 0 2+? Autumn 1989: Perfect match with 3 different neutrino species.

23 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen LEP, the Top and the Higgs H t g b jets The “tune” of the bb-note has a nearly imperceptible “overtone” due to the presence of the higgs and the top quarks This overtone can be measured and calculated from the Standard Model with the higgs mass and the top mass as free parameters Predictions: top mass ≈ 175 GeV and higgs mass < 1000 GeV

24 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen LEP and the Higgs Fermilab found the top with mass as predicted from LEP: Standard Model Higgs: M H < 1000 GeV Lightest Super Symmetric Higgs M h < 200 GeV Best fit : M h ≈ 100 GeV Within reach of LEP200 !

25 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Is the Higgs Idea falsified ?

26 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Higgs Hunting with LEP (Total energy 206.6 GeV) e-e- e+e+ H (115 GeV) Z (91 GeV) two Higgs jets containing B-particles two Z jets 2.5  effect for a Higgs Particle at 115 GeV (e - + e + ) -----> (Z 0 + H) -----> 4 jets

27 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen ALEPH DELPHI

28 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen B - Particles in DELPHI

29 CERN, 8 February, 2001 Egil Lillestøl, CERN & Univ. of Bergen Questions for the LHC - Does Higgs Particles exist ? - Can all the Forces and Particles be unified ? (Super Symmetry) - Is Dark Matter made of Super Symmetric Particles ? - What happened to the Antimatter in the Universe ? - Did the Universe go through a Phase of Quark-Gluon Plasma ? - Are the Fundamental Particles two-dimensional Strings ? - Does the Universe have more than three Spatial Dimensions ? - Are there more Forces and Particles to be discovered ? - Accelerating Expansion of the Universe and Dark Matter - Could everything be just wrong ? The LHC Experiments will be very Exciting !


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