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The Big Bang, the LHC and the Higgs Boson

The Big Bang, the LHC and the Higgs Boson. Dr Cormac O’ Raifeartaigh (WIT). Overview. I. LHC What, How and Why II. Particle physics The Standard Model III. LHC Expectations T he Higgs boson and beyond Big Bang Cosmology. High-energy proton beams Opposite directions

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The Big Bang, the LHC and the Higgs Boson

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  1. The Big Bang, the LHC and the Higgs Boson Dr Cormac O’ Raifeartaigh (WIT)

  2. Overview I.LHC What, How and Why II. Particle physics The Standard Model III.LHCExpectations The Higgs boson and beyond Big Bang Cosmology

  3. 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

  4. Explore fundamental constituents of matter Investigate inter-relation of forces that hold matter together Study early universe Highest energy since BB Why Mystery of dark matter Mystery of antimatter

  5. Cosmology E = kT → T =

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

  7. Particle detectors

  8. Careers • Mathematics theory • Theoretical physics expected collisions • Experimental physicists experiments • Engineers detector design • Computer scientists world wide web • Software engineers GRID

  9. Particle physics (1930s) • atomic nucleus (1911) • most of atom empty • electrons outside • inside the nucleus • proton (1909) • neutron (1932) Periodic Table: determined by protons • strong nuclear force?

  10. 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: Radioactivity The atom

  11. Splitting the nucleus (1932) Cockcroft and Walton: linear accelerator Accelerator used to split the nucleus H1 + Li3 = He2 + He2 Verified mass-energy (E= mc2) Verified quantum tunnelling Nobel prize (1956) Cavendish Lab, Cambridge (1928)

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

  13. Particle physics (1950s) Cosmic rays Particle accelerators π+ → μ + + ν cyclotron

  14. Particle Zoo Over 100 particles

  15. new periodic table p,n not fundamental symmetry arguments quarks new fundamental particles UP and DOWN prediction of - Quarks (1960s) Stanford experiments 1969 Gell-Mann, Zweig

  16. Six different quarks (u,d,s,c,t,b) Strong force = quark force Six leptons (e,μ,τ, υe,υμ,υτ) Gen I: all of matter Quark model Gen II, III redundant

  17. Electro-weak unification • Unified field theory • em + w = e-w interaction • Mediated by W and Z bosons • Higgs mechanism to generate mass • Predictions • Weak neutral currents (1973) • W and Z gauge bosons (CERN, 1983) Rubbia, Van der Meer Nobel prize

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

  19. Standard Model : particles • Success of QCD, e-w • many questions Higgs boson outstanding

  20. Higgs boson 120-180 GeV Set by mass of top quark, Z boson Search III. LHC expectations

  21. Extensions of Standard Model Grand unified theory (GUT) Theory of everything (TOE) Supersymmetry symmetry of bosons and fermions improves GUT circumvents no-go theorems Theory of Everything Phenomenology Supersymmetric particles? Broken symmetry Beyond the SM: supersymmetry

  22. Expectations II: cosmology √1. Exotic particles √ 2. Unification of forces 3. Nature of dark matter? neutralinos? 4. Matter/antimatter asymmetry? LHCb High E = photo of early U

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

  24. 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

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