1. Thomas Lohse Humboldt-Universität zu Berlin Thomas Lohse Humboldt-Universität zu Berlin Stuff and Glue Particles and Forces Experimental methods What is matter? Which forces stabilize matter? Open questions and the next steps

2. Greek Philosophy Empedokles ( 500-430 B.C.) –four elements: fire, water, earth, air –two fources: love, hatred  mixing, separating Platon ( 427-347 B.C.) –symmetric shapes: beauty of laws of nature Demokrit ( 460-371 B.C.) –atoms: different forms and weights –emptiness: binding and motion in the void firewaterearthair

3. How to resolve structures? eye: ~1 mm resolution scattering of photons: lense: ~ 0.1 mm resolution light microscope: ~ 1 µ m Limited by

4. How to resolve structures? particle scattering: Rutherford scattering: E = O(MeV) α-particles λ = O(fm) gold atoms with nuclei modern particle accelerators, e.g. HERA: e(27 GeV) on p(920 GeV) resolution 0.001 fm

5. TV tube a) linear accelerators Fermilab injector the principle superconducting RF cavity for future linear collider TESLA SLAC linac first linear collider Particle Accelerators

6. b) storage rings Particle Accelerators

7. c) the big labs in Europe DESY (Hamburg) CERN (Geneva ) LEP SPS

8. Particle Detection display of electronic signals OPAL detector at LEP, CERN

9. Two Topologies Colliding beams (e + e –, ep, pp...) Myon Chambers Hadron Calorimeter Tracking Chamber Electromagn. Calo. e–e– cylindrical shell structure of subdetectors cylindrical shell structure of subdetectors

10. Two Topologies Fixed target (μ – A, pA,...) Forward layer structure of subdetectors Forward layer structure of subdetectors HERA-B 21 m Si-vertex detector tracking system magnet RICH detector EM calorimeter hadron absorber & muon system hadron absorber & muon system

11. Subdetector Tasks 40 cm Silicon Microstrip Wafers => vertex tracking typical impact parameters O(100 μm) Proportional Drift Chambers => main tracking typical coordinate resolution O(200 μm) magnetic field => particle momentum from curvature

12. Subdetector Tasks HERA-B RICH Particle Identification: example Ring Imaging CHerenkov detectors Ring radius => p/m => π,K,p sep. charged particle in radiator gas mirror light detector (e.g. PM tubes) Cherenkov cone point on Cherenkov ring

13. Subdetector Tasks Calorimeters (lead, steel, uranium...) electromagnetic showers => e,γ energy hadronic showers => energy of hadrons penetrating particles => muons

14. Structure of Matter Crystal Molecule Nucleus Atom elements of normal matter: quarksleptons up Q = +2/3 neutrino Q = 0 down Q = –1/3 electron Q = –1 neutrinos: from β-decay / sun burning quarks: always bound, ”confinement“

15. How to see the quarks accelerators => high energy quarks quarks => jets of secondary hadrons jet e+e+ e–e– quark antiquark

16. How to measure quarks in the proton accelerators => knock quarks out of protons final state kinematics => initial quark momentum jet e

17. Quantitative: proton structure functions quark densities in the proton as function of the quark momentum and the resolution of the scattering quark densities in the proton as function of the quark momentum and the resolution of the scattering

18. Heavier short-lived Generations very strange mass spectrum... High energy collisions reveal heavier versions of quarks and leptons! up... charm... top down... strange... bottom electron... muon... tau ν e... ν μ... ν τ

19. Strong Similarity to... groups periods

20. The Periodic System of Elementary Particles u-quark group d-quark group neutrino group electron group quark/lepton periods I II III particle physics: periods = families

21. More Families??? LEP: visible invisible Γ Z = Γ vis + Γ invis Γ invis = N fam · Γ ν measurements: N fam = 3 lineshape of Z resonance from LEP

22. Forces: Exchange of Field Quanta repulsive attractive

23. The Fundamental Forces forcequantamassrange gravity graviton(?)0 electromagnetic photon 0 weak W ±, Z80, 90GeV~.001 fm strong gluons0O(1) fm N S q q p p n n n n p p p p p n n n p p n p n p (confinement)

24. Gamma Quantum in Action γ

25. Gluon Quantum in Action

26. W Quanta in Action

27. Z Quanta in Action

28. The Complete(??) Picture

29. Supersymmetry: still a hypothesis... Matter Particles Spin 1/2 Superpartners of Matter Particles Spin 0

30. Supersymmetry: still a hypothesis... Force Particles Superpartners of Force Particles

31. Why is the Weak Force Weak? ep cross section vs. squared momentum transfer electromagnetic weak unification at γ W e ν It isn‘t weak at all!!! It is just a mass effect!!! It isn‘t weak at all!!! It is just a mass effect!!!

32. A Unified Single Force? We have just seen this: Electroweak unification E = 100 GeV like 10 -10 s after big bang Grand electroweak/strong unification E = 10 14 GeV like 10 -35 s after big bang Planck Scale: unification with gravity E = 10 19 GeV like 10 -43 s after big bang

33. Big Bang

34. Why such funny asymmetric masses of force particles? Hypothesis: There is a background field in the universe... the Higgs field Vacuum field strength Symmetric potential energy Initial state of the universe Inflation: spontaneous symmetry breaking Inflation: spontaneous symmetry breaking Asymmetric ground state: masses are created a Higgs particle appears Asymmetric ground state: masses are created a Higgs particle appears

35. A conference banquet...The nobel prize winner enters the room... The physicists next to him turn immediately to talk to him. It becomes hard for him to move (accelerate). He is effectively massive... physicists = background Higgs field nobel prize winner = massive particle How does Mass Creation Work?

36. A conference banquet...A rumour is injected...The physicists cluster where the rumour spreads out. It gets hard for the rumour to move (accelerate)... rumour = Higgs particle The Higgs particle is itself massive!

37. And Where is the Higgs? direct search not yet successful: m H > 114 GeV Higgs mass enters via quantum corrections in precision measurements

38. Why such a strange mass spectrum ? Does the Higgs particle exist ? Why three families ? Open Questions ? ? Why symmetric lepton/quark structure ? Is there a unified force ? Supersymmetric partners of particles and fields ? Characteristic pattern of quark family transistions ? Transitions in lepton family ? Where/how is the antimatter gone ? What about gravity ? Extra space-time dimensions?...

39. The next big steps: (1) LHC / CERN ATLAS detector LHC: 7 TeV protons on 7 TeV protons Start of operation: 2007-2008 LHC: 7 TeV protons on 7 TeV protons Start of operation: 2007-2008 LHC goals: establish the Higgs particle search for supersymmetry search for new effects LHC goals: establish the Higgs particle search for supersymmetry search for new effects accessible mass scale: ~1 TeV

40. The next big steps: (2) TESLA / DESY 33 km linear e + e – -collider, energy 500-800 GeV Similar projects proposed by U.S.A. and Japan start not before 2013 33 km linear e + e – -collider, energy 500-800 GeV Similar projects proposed by U.S.A. and Japan start not before 2013 TESLA goals: detailed properties of Higgs particle highest precision tests of electroweak force detailed properties of supersymmetric particles search for extra dimensions... TESLA goals: detailed properties of Higgs particle highest precision tests of electroweak force detailed properties of supersymmetric particles search for extra dimensions...

41. It stays interesting...

42. ? ?