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Unraveling The LHC: Milestones, Discoveries, and Ongoing Experiments

Explore the journey of the Large Hadron Collider (LHC) at CERN, from its construction to its groundbreaking discoveries. Learn about the Standard Model fields, fermions, and masses, as well as ongoing experiments like ATLAS, LHCb, ALICE, and CMS. Discover the collider's superconducting technology, massive energy levels, and the quest for understanding fundamental particles and forces. Dive into topics like strong and weak interactions, the Higgs sector, electroweak phenomena, and the search for new physics beyond the Standard Model. Keep up with the latest research papers, experimental results, and the quest for dark matter at the LHC.

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Unraveling The LHC: Milestones, Discoveries, and Ongoing Experiments

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  1. The LHC the story so far Alan BarrUniversity of Oxford PASCOS, July 2011

  2. The Standard Model Fields (Maxwell, Weak, Strong) Fermions (Dirac…) Masses & potentials. (Untested) + other terms?

  3. The accelerator… 1232 x 14.3 m dipoles Superconducting Superfluid (1.9K)Liquid Helium Cooled 7 TeV CM energy 14 TeV ~1 GJ Magnetic Energy ~100 MJ Beam Energy 1 MJ melts 1.5 kg Cu

  4. 2 x general-purpose experiments energy, momentum, identification controlled environment ~ 109 collision / second ~ decade of operation LHCb ATLAS ALICE CMS

  5. ATLAS Segment of 4π detector

  6. Local Interest: ATLAS Semiconductor Tracker… Cambridge: Silicon R&D, testing Robotic assembly

  7. A year is a long time at the LHC Commissioned bunch trains 50 ns bunch-crossing operation

  8. 1 fb-1 target PASCOS 2010  0.0002 fb-1

  9. Sure things @ TeV-scale ~ 100 physics publications on collision data from CMS + ATLAS Strong interaction Weak interaction Higgs Sector or other Electroweak SB Flavours 3rdgeneration quarks (t and b) CP violation

  10. ATLAS Strong interactions • Self-interacting force carriers • Perturbative regime • Jets of hadrons • Radiation from accelerated colour • Backgrounds to all other searches • Non-perturbative • Quark-gluon plasma • Nucleon structure

  11. CMS-QCD-10-011 Agreementover 10 decades NLO Monte Carlo DATAdeconvolved Uncertaintiesin Jet EnergyScale understood

  12. ATLAS-CONF-2011-081 Dijets @ muliti-TeV CM Energy = 4 TeV ATLAS

  13. Strong interactions – papers Inelastic cross section Jet cross sections Jet shapes Dijet azimuthal decorrelations Dijet resonances Underlying event Charged hadron distributions Bose-Einstein correlations Strong contact interactions Event shapes

  14. Weak interactions WW ZZ Masses and couplings well known Self-interactions under study Cross-sections diverge without new physics

  15. Electroweak cross sections

  16. ATLAS-CONF-2011-060 W + Jets Electroweak + strong radiation Background to many searches Test MC simulations

  17. Excludes SM-like Z’ M<1.41 TeV After you understand the Z… ATLAS-CONF-2011-083

  18. Higgs sector – the model LHC sensitivity to almost all SM Higgs masses 2011-12 Field couples to mass Scalar potential Vacuum expectation value W, Z masses via Higgs/gauge interactions Fermion masses via Higgs/Yukawa coupling Field excitation = Higgs boson(s)

  19. Higgs boson production and decay • Coupling  mass • Production • Gluon fusion • Weak boson fusion • Decay • To heaviest allowed states

  20. Higgs search status

  21. Higgs  WW (search)

  22. Higgs   (search)

  23. Last week: full ATLAS search Higgs analysis of 2010 data

  24. 3rd Generation: t and b Three generations needed for CP violation Nearly decoupled from first two generations Long lived b-quark hadrons Standard Model: top Higgs coupling ~unity Radiative corrections from top on mH Role in electroweak symmetry breaking?

  25. Papers (flavour) arXiv:1106.0902 • Cross sections • and single • jets • Upsilon () • J/Psi () • Strange

  26. ATLAS-CONF-2011-087

  27. More speculative (perhaps?)… Further generations Unification of forces Supersymmetry WIMPs Compositeness / substructure New gauge forces / particles Strong gravity Extra dimensions Something else?

  28. Further search papers • Others • Monojets • e-mu resonances • Dilepton resonances • Leptoquarks • CHAMPS • Dimuons (contact) • W' l  • Z'  ll • Supersymmetry: • Squarksor gluinos • Lepton + jet + invis • Dilepton + invis • Same sign leptons + invis • Z + invis • b-jet(s) + invis • R-hadrons

  29. Supersymmetry Partner particles Spin differ by ½ Stabilise mH Dark Matter candidates “Missing” momentum Big reach at LHC

  30. Supersymmetry searches 3 June 2011 25 Feb 2011 ATLAS-CONF-2011-086 arXiv:1106.5048 “Missing” momentum Scalar sum of momentum

  31. Interpretation ATLAS-CONF-2011-086 Simplified model Squark, gluino, massless neutralino Exclude mq = mg< 1.02 TeV Degenerate points harder

  32. Wider interpretation... ATLAS 0/1 leptonATLAS-CONF-2011-086 CMS αT Cassel, Ghilencea, Kraml, Lessa, Ross http://arxiv.org/abs/1101.4664 Allanach, Khoo, Lester, Williams http://arxiv.org/abs/1103.0969 Regions with low fine tuning Points sampled from fits to global data Global CMSSM fits Alan Barr, University of Oxford

  33. Getting the results? • ATLAS • Public results: link • CMS • Public results: link • Recent conference • Physics at the LHC 2011, ;link • Upcoming new results: • EPS 2011, 21-27 July; link

  34. Conclusions • Excellent operation of LHC and detectors • > 1 fb-1 • Remarkable degree of control • New Physics Searches leading the world • Supersymmetry / WIMPs • Resonances • Substructure • … • Sufficient data for Higgs search • Over wide range of SM cross-sections • Full range by end 2012?

  35. LHC PHYSICS Extra slides

  36. 2011 Plans…

  37. Software Operations Hardware Grid Detector & Upgrade Computing

  38. http://indico.cern.ch/conferenceDisplay.py?confId=100963

  39. Large Hadron Collider 1 MJ melts 1.5 kg Cu

  40. W charge asymmetry Vector – Axial couplings (Chiral couplings) Probe proton structure (Parton distributions) Cancellation of systematic uncertainties

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