The Big Bang, the LHC and the God Particle

1. Black Holes, the LHC and the God Particle Dr Cormac O’Raifeartaigh (WIT) The Big Bang, the LHC and the God Particle Cormac O’Raifeartaigh (WIT)

2. Overview I.LHC What, why, how II. A brief history of particles From the nucleus tothe Standard Model III.LHCExpectations The God particle Beyond the Standard Model Cosmology at the LHC E = mc2

3. Particle accelerator Head-on collision of protons Huge energy density Create short-lived particles Detection The Large Hadron Collider (CERN) No black holes

4. I. Explore fundamental constituents of matter Investigate inter-relation of forces that hold matter together II. Study early universe Highest energy since BB Why • T = 1019 K • t = 1x10-12 s • V = football • Puzzle of antimatter • Puzzle of dark matter

5. Cosmology E = kT → T =

6. Ultra-high vacuum Low temp: 1.6 K v = speed of light E = 14 TeV (2.2 µJ) How LEP tunnel: 27 km Superconducting magnets 600 M collisions/sec (1.3 kW)

7. Particle detectors • 4 main detectors • CMS multi-purpose • ATLASmulti-purpose • ALICEquark-gluon plasma • LHC-bantimatter decay UCD group

8. Particle detectors • Tracking device measures momentum of charged particle • Calorimeter measures energy of particle by absorption • Identification detector measures velocity of particle by Cherenkov radiation

9. Matter and Energy • Matter is a form of energy E = mc2 • Energy is a form of matter m = E/c2 → Create matter and antimatter from energy

10. Antimatter • Predicted by Dirac Equation • Electron of opposite charge • Detected 1932 • All particles have opposites Why is universe dominated by matter?

11. Black Holes • Huge mass shrunk to tiny volume • Extreme gravitational field • Light, matter ‘trapped’ Huge energy required m = E/c2

12. II Particle physics (1930s) • Atoms (1909) • Brownian motion • The atomic nucleus (1911) • Rutherford Backscattering • Proton(1918) • Neutron (1932)

13. Protons and the Periodic Table • Fundamental differences in atoms • no. protons in nucleus • Determines electron configuration • Determines chemical properties What holds nucleus together? What causes radioactivity?

14. strong force >> em charge indep (p+, n) short range Heisenberg Uncertainty massive particle 3 charge states Strong force (Yukawa, 1934) Yukawa Yukawa pion (1947)

15. Weak force (Fermi, 1934) Radioactivity (B decay) Electrons from nucleus? no p+ + e-? But: energy, momentum missing New particle; tiny mass, zero charge neutrino no p+ + e- +  (confirmed 1956)

16. Four forces of nature • Force of gravity Holds cosmos together Long range • Electromagnetic force Holds atoms together • Strong nuclear force: holds nucleus together • Weak nuclear force: Beta decay

17. Walton: accelerator physics Cockcroft and Walton: linear accelerator Protons used to split the nucleus (1932) 1H1 + 3Li6.9 → 2He4 + 2He4 Verified mass-energy (E= mc2) Verified quantum tunnelling Cavendish lab, Cambridge Nobel prize (1956)

18. New particles (1950s) Cosmic rays Particle accelerators LINACS (Walton) synchrotrons π+ → μ+ + ν

19. Particle Zoo (1950s, 1960s) Over 100 particles

20. p not fundamental new periodic table symmetry arguments new fundamental particles quarks Up, down, strange prediction of - Quarks (1960s theory) Gell-Mann, Zweig

21. Stanford experiments 1969 Scattering experiments Similar to RBS SF = interquark force! defining property = colour confinement infra-red slavery Quarks (experiment, 1970s) The energy required to produce a separation far exceedsthe pair production energy of a quark-antiquark pair

22. 30 years experiments Six different quarks (u,d,s,c,t,b) Six leptons (electron sisters) (e,μ,τ, υe,υμ,υτ) Gen I: all of ordinary matter Gen II, III redundant? Quark generations (1970s –1990s)

23. Electro-weak force (1970s) • Electromagnetic + weak forces = e-w force • Single interaction above 100 GeV • Mediated by new particles W, Z • Higgs mechanism to generate mass Predictions: W+-,Z0 bosons Detected: CERN, 1983 Glashow, Salaam and Weinberg Nobel prize 1979 Rubbia, Van der Meer Nobel prize 1984

24. EM + weak force = electroweak Strong force = quark force (QCD) Force between quarks caused by colour Matter particles: fermions Force particles: bosons The Standard Model (1970s)

25. Standard Model: 1980-1990s • experimental success but Higgs bosonoutstanding key particle: too heavy?

26. Higgs boson Determines mass of other particles Set by known mass of top quark, Z boson 120-180 GeV Search…surprise? III LHC expectations (SM)

27. Main production mechanisms of the Higgs at the LHC Ref: A. Djouadi, hep-ph/0503172

28. Higgs search: summary Ref: hep-ph/0208209

29. Unified field theory Grand unified theory (GUT): 3 forces Theory of everything (TOE): 4 forces Supersymmetry symmetry of fermions and bosons improves GUT (circumvents no-go theorems) gravitons: makes TOE possible LHC Supersymmetric particles? Extra dimensions? Expectations II: Beyond the SM

30. Expectations III: Cosmology • Superforce: SUSY particles? 2. SUSY = dark matter? neutralinos? double whammy 3. Missing antimatter ? LHCb High E = photo of early U

31. Tangential to ring B-meson collection Decay of b quark, antiquark CP violation (UCD group) LHCb (UCD) • Where is antimatter? • Asymmetry in M/AM decay • CP violation b-quarks, W,Z bosons June 2010

32. Higgs boson (God particle) Close chapter on SM Supersymmetric particles Open chapter on unification Cosmology Missing antimatter Nature of dark matter Surprises New dimensions - string theory? Summary Further reading: ANTIMATTER

33. World leader 20 member states 10 associate states 80 nations, 500 univ. Ireland not a member Epilogue: CERN and Ireland European Organization for Nuclear Research No particle physics in Ireland…..almost