Re-creating the Big Bang

1. Re-creating the Big Bang Walton, CERN and the Large Hadron Collider Albert Einstein Ernest Walton Dr Cormac O’ Raifeartaigh (WIT)

2. Overview I.LHC What, why, how II. A brief history of particles From the atom tothe Standard Model III.LHCExpectations The Higgs boson Beyond the Standard Model

3. World leader 20 member states 10 associate states 80 nations, 500 univ. Ireland not a member CERN European Organization for Nuclear Research No particle physics in Ireland

4. High-energy proton beams Opposite directions Huge energy of collision E = mc2 Create short-lived particles Detection and measurement The Large Hadron Collider No black holes

5. E = 14 TeV λ =1 x 10-19 m Ultra high vacuum Low temp: 1.6 K How LEP tunnel: 27 km Superconducting magnets

6. Particle detectors

8. Explore fundamental constituents of matter Investigate inter-relation of forces that hold matter together Glimpse of early universe Answer cosmological questions Why • t = 1x10-12 s • V = football Highest energy since BB

9. Cosmology E = kT → T =

10. Particle cosmology

11. Tangential to ring B-meson collection Decay of b quark, antiquark CP violation (UCD group) LHCb • Where is antimatter? • Asymmetry in M/AM decay • CP violation Quantum loops

12. Discovery of electron • Crooke’s tube cathode rays • Perrin’s paddle wheel mass and momentum • Thompson’s B-field e/m • Milikan’s oil drop electron charge Result: me = 9.1 x 10-31 kg: TINY

13. Atoms: centenary • Maxwell (19th ct): atomic theory of gases • Dalton, Mendeleev chemical reactions, PT • Einstein: (1905): Brownian motion due to atoms? • Perrin (1908): measurements λ = λ = Perrin (1908) Einstein

14. The atomic nucleus (1911) • Most projectiles through • A few deflected backwards • Most of atom empty • Atom has nucleus (+ve) • Electrons outside Rutherford (1911)

15. Nuclear atom • +ve nucleus 1911 • proton (1909) Periodic Table: determined by protons • neutron (1932) • strong nuclear force?

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 The atom

17. Splitting the nucleus Cockcroft and Walton: linear accelerator Protons used to split the nucleus (1932) H + Li = He + He Verified mass-energy (E= mc2) Verified quantum tunnelling Nobel prize (1956)

18. Born in Dungarvan Early years Limerick, Monagahan, Tyrone Methodist College, Belfast Trinity College Dublin (1922) Cavendish Lab, Cambridge (1928) Split the nucleus (1932) Trinity College Dublin (1934) Erasmus Smith Professor (1934-88) Ernest Walton (1903-95)

19. Nuclear fission • fission of heavy elements Meitner, Hahn • energy release • chain reaction • nuclear weapons • nuclear power

20. SF >> em protons, neutrons charge indep short range HUP massive particle Yukawa pion 3 charge states Strong force

21. New particles (1950s) • Cosmic rays Particle accelerators cyclotron π+ → μ + + ν

22. Particle Zoo Over 100 particles

23. new periodic table p+,n not fundamental isospin symmetry arguments (SU3 gauge group) prediction of - SU3 → quarks new fundamental particles UP and DOWN Stanford experiments 1969 Quarks (1960s) Gell-Mann, Zweig

24. scattering experiments colour chromodynamics asymptotic freedom confinement infra-red slavery Quantum chromodynamics The energy required to produce a separation far exceeds the pair production energy of a quark-antiquark pair,

25. Six different quarks (u,d,s,c,t,b) Six leptons (e,μ,τ, υe,υμ,υτ) Gen I: all of matter Gen II, III redundant Quark generations

26. Gauge theory of e-w interaction • Unified field theory of e and w interaction Salaam, Weinberg, Glashow • Above 100 GeV • Interactions of leptons by exchange of W,Z bosons and photons • Higgs mechanism to generate mass • Predictions • Weak neutral currents (1973) • W and Z gauge bosons (CERN, 1983)

27. Matter: fermions quarks and leptons Force particles: bosons QFT: QED The Standard Model (1970s) • Strong force = quark force (QCD) • EM + weak = electroweak • Prediction: W+-,Z0 boson • Detected: CERN, 1983

28. Standard Model (1970s) • Success of QCD, e-w • Higgs boson outstanding many questions

29. Higgs boson 120-180 GeV Set by mass of top quark, Z boson Search Today: LHC expectations

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

31. Decay channels depend on the Higgs mass: Ref: A. Djouadi, hep-ph/0503172

32. For low Higgs mass mh 150 GeV, the Higgs mostly decays to two b-quarks, two tau leptons, two gluons and etc. • In hadron colliders these modes are difficult to extract because of the large QCD jet background. • The silver detection mode in this mass range is the two photons mode: h   , which like the gluon fusion is a loop-induced process.

33. A summary plot: Ref: hep-ph/0208209

34. Super gauge symmetry symmetry of bosons and fermions removes infinities in GUT solves hierachy problem Grand unified theory Circumvents no-go theorems Gravitons ? Theory of everything Phenomenology Supersymmetric particles? Broken symmetry Beyond the SM: supersymmetry

35. Expectations III: cosmology √ 1. Exotic particles √ 2. Unification of forces 3. Missing antimatter? LHCb 4. Nature of dark matter? neutralinos? High E = photo of early U

36. Higgs boson Close chapter on SM Supersymmetric particles Open chapter on unification Cosmology Missing antimatter Nature of Dark Matter Unexpected particles Revise theory Summary

37. 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