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Conference Summary

Conference Summary. ICHEP 2004, Beijing John Ellis CERN. Barbieri. The Basis of Particle Physics. String theory. Cosmology. Future accelerators. @ HERA. Crucial For LHC. Klein. QCD Works!. @ Tevatron. Lucchesi. b production. world average (MSbar, NNLO).

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Conference Summary

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  1. Conference Summary ICHEP 2004, Beijing John Ellis CERN

  2. Barbieri The Basis of Particle Physics String theory Cosmology Future accelerators

  3. @ HERA Crucial For LHC Klein QCD Works! @ Tevatron Lucchesi b production

  4. world average (MSbar, NNLO) αS(MZ) = 0.1182  0.0027 cf. (2002) 0.1183  0.0027 Stirling World Summary of αS(MZ) – July 2004 Bethke , hep-ex/0407021

  5. W, Z cross sections jets on way Stirling NNLO pQCDCalculations Parton splitting functions + 7 pages!Moch, Vermaseren & Vogt

  6. Stirling QCD Calculations in String Approach Cachazo, Svrcek & Witten • Maximal helicity-violating (MHV) amplitudes as effective vertices in a new scalar graph approach • use them with scalar propagators to calculate • tree-level non-MHV amplitudes • with both quarks and gluons • … and loop diagrams! • dramatic simplification: compact output in terms of familiar spinor products • phenomenology? multijet cross sections at LHC, etc. underway

  7. Dunlop QCD phase diagram Hadron gas

  8. Dunlop Particle Production Ratios Well described by simple thermodynamic model, T ~ lattice … … but could these just be phase space and statistics?

  9. Peripheral Collisions z y x Anisotropic Flow but hydrodynamic model fails to reproduce HBTsource size Dunlop Elliptic Flow: the Shape of the Interaction Region at RHIC Shape parameter v2 Reproduced well by hydrodynamic model

  10. Dunlop Hadron Elliptic Flows Scale with Quark Number

  11. Dunlop Jet Quenching @ RHIC … … due to parton energy loss in QGP?

  12. Dunlop The State of Heavy-Ion Theory • A patchwork, with model parameters adjusted independently for different observables. • Statistical equilibriation or phase space? • Hydrodynamical model: EOS vs realistic quark-gluon calculations? • Source size as measured by HBT? • Parton energy loss: promising development! • Watch out for J/ψ suppression! • For compelling QGP claim, need quantitative estimates of theoretical uncertainties

  13. Questions on Hadron Spectroscopy • Do (which) pentaquarks exist? • Do other exotic hadrons exist? • What are the quark descriptions of the DsJ(2317) and DsJ(2460)? • Does the DsJ(2632) exist (SELEX)? • What is the quark description of the X(3872)? • Interpretation of threshold reported states? • Fate of 12% rule in ψ’ decay (BES)?

  14. Jin Some Sightings of the Θ+(1530) … … but many negative searches

  15. Summary of Positive Results

  16. Inconsistencies in Mθand Γθ? Jin (LEPS) M(nK+)≠ M(pKs)? Also width of θ+(1540) - Two “positive” experiments: HERMES: Γθ= 17 9  2 MeV ZEUS: Γθ= 8  4 MeV K+N PWA indicates Γθ< 1 MeV

  17. Summary of Negative Results

  18. Jin How Significant are Negative Results? • Compare with production of other baryons resonances • Λ(1520) may not be most reliable guide • Most positive results at lower energies • Different production mechanisms for exotic baryons?

  19. Close Interpretations of θ+(1530) – if it exists • Naïve non-relativistic quark model would need epicycles: di/triquarks, P-wave ground state • Predicted in chiral soliton model: fits data, predicts other exotic states • Existence requires confirmation: a high-statistics, -significance experiment • If it exists, θ+ spin & parity distinguish models ← Based on idea that quarks weigh << ΛQCD The stakes are high: the θ+(Ξ­­, θc) may take us beyond the naïve quark model

  20. Also reported in ωJ/ψ: mixed isospin would → mixing with D0D*0 molecule Close Belle BK X(3872) M(p+p-p0) Jin X(3872): Charmonium or D0D*0 “Molecular State”? at 90% C.L. y’ppJ/y Belle, also CDF, D0 X(3872) 10σeffect No D0D0→ unnatural spin-parity

  21. J/ygpp BES II acceptance weighted BW +3 +5 -10 -25 M=1859 MeV/c2 G < 30 MeV/c2 (90% CL) c2/dof=56/56 0 0.1 0.2 0.3 M(pp)-2mp(GeV) 3-body phase space acceptance Jin Hadronic Threshold States also pΛ, pΛc, KΛ, ππ,πΚ Quark description inadequate: need hadronic description? molecules, …?

  22. Teubert Electroweak Physics Low Energy vs High Energy NuTeV: EW corrections - 1σ? Strange sea - 1σ? ubar ≠ dbar - 1σ? (NOMAD) APV, E158 compatible with expected running of α(Q2)

  23. Future Tevatron Prospects Denisov Top-Quark Mass: Run 1 Revisited new D0: improved Run 1 value Implications for fit to Higgs mass …

  24. Teubert The Blue Band Plot Global electroweak fit – high Q2 data Since Aachen EPS Summer 2003: new top mass increases mH by ~20 GeV new 2-loop terms etc. increase mH by ~6 GeV new BES et al

  25. How Good is the Global Electroweak Fit? Teubert Pulls on Global Fit Higgs mass from individual measurements Direct search limit Heavy flavours ≠ leptons, mW

  26. h → tt requiresexcellent low-pT lepton + tau jet trigger fb-1 1 year @1034 1 year @1033 time 1 month @1033 LHC: ATLAS Values for single experiment Looking for Standard-Model Higgs Denisov, Barr //

  27. Flavour Physics: Some Questions • Are the data on quark mixing described by the CKM model? • Are there signatures of physics beyond the SM? • If not, why is new physics flavour-blind? • Why is neutrino mixing so different from quark mixing? • Can they be related? Sakai, Ali, Giorgi, Ligeti, Patera, Shipsey, Langacker, McGrew, Wang

  28. Patera New Determinations of Vus Vus x f+(0) • PDG02 CKM unitarity ‘crisis’ has disappeared

  29. Sakai, Ali, Giorgi, Ligeti Global CKM Fit Matrix elements from lattice: Hashimoto

  30. Compare sin2 & s-Penguin Results φK0 has moved towards SM η’ Ks at 2.6 from sin2[cc] <s-penguins>at 3.5 from sin2[cc] BUT: expect corrections to sin2[cc] for many modes Sakai, Ali, Giorgi, Ligeti

  31. Measuring α with B→ ππ, ρπandρρ Decays + 12 - 10 100 Excellent agreement with global CKM fit

  32. CP Violation in B0→ K+π- First evidence for direct CPV in B decays Sakai, Ali, Giorgi, Ligeti Discrepancy with ACP(K+π0 ) = 0.04  0.05  0.02 ? Electroweak penguins? NP? Final-state interactions?

  33. Putting all the Information Together Is there room for NP? Sakai, Ali, Giorgi, Ligeti

  34. Ligeti Still Room for Future Progress

  35. Patera Im lt = A2l3 h a h KL→p0e+e- KL→p0m+m- g b KS→p0e+e- KS→p0m+m- KL→p0gg The connection of the KLp0e+e-(m+m-) decays to lt needs work on ancillary modes Bounds & prospects for KL→ π0νν Rare KDecays More handles on triangle KS → π0l +l-, π0γγ important for KL → π0l +l- Results & prospects for K+ → π+νν

  36. Neutrino Masses & Oscillations • First confirmed physics beyond SM • LSND? Waiting for MiniBooNE • (Near) bimaximal mixing ≠ quarks: Is there a relation: θν+θc = π/4? Reactors for θ13? • Dirac or Majorana masses: seesaw? Normal or inverted hierarchy? ββ0ν? • Holy Grail: CP violation via phase δ? Indirect relation to cosmology via baryogenesis? • Search for violation of charged lepton numbers Langacker

  37. Oscillation Decay Decoherence L/E Significance Evidence for Neutrino Oscillation Pattern from Super-Kamiokande & KamLAND Δχ2 (neutrino decay – oscillation) =11.4  3.4 σ Δχ2 (neutrino decoherence – osc’n)=14.6  3.8 σ The dips in the data cannot be explained by other models Wang

  38. KamLAND consistent with SK/SNO sin2q is determined by SK/SNO KamLAND SK/SNO Wang

  39. K2K confirms Super-Kamiokande … agree with SK azimuthal distributions and L/E analysis K2K Rate suppression and spectral distortion … McGrew, Wang

  40. Physics beyond the SM • The most pressing issue is breaking EW symmetry • Must be solved below 1 TeV energy • Would be a revolution in fundamental physics • Basis for any further theoretical speculations • Hints of grand unification: gauge couplings, neutrino masses, but wait and see • String unification is still the dream Barbieri

  41. Breaking Electroweak Symmetry • Calculability principle: EW scale should be calculable in terms of other mass scale • No quadratic divergences: supersymmetry ? or Higgs as pseudo-Goldstone boson ? • Supersymmetry: also gauge unification and dark matter • LEP data: some fine-tuning needed Barbieri

  42. Alternatives to Supersymmetry • Interpretation of EW data? consistency of measurements?Discard some? • Higgs + higher-dimensional operators? corridors to higher Higgs masses? • Little Higgs models extra `Top’, gauge bosons, `Higgses’ • Higgsless models strong WW scattering, extra D? Barbieri

  43. Little Higgs Models • Embed SM in larger gauge group • Higgs as pseudo-Goldstone boson • Cancel top loop with new heavy T quark • New gauge bosons, Higgses • Higgs light, other new physics heavy MT < 2 TeV (mh / 200 GeV)2 MW’ < 6 TeV (mh / 200 GeV)2 MH++ < 10 TeV Not as complete as susy: more physics > 10 TeV

  44. Why the 10% τ - e+e- discrepancy above ρ peak? gμ - 2: e+e- Data vs τ Data Largest contributions, errors from low energies zoom zoom KLOE agrees with CMD-2: discard τ data Teubert

  45. Updated Results for gμ - 2 Weak contribution : aweak = + (15.4 ± 0.3)  10 –10 Hadronic contribution from higher order : ahad [( /)3] = – (10.0 ± 0.6)  10 –10 Hadronic contribution from LBL scattering: ahad [LBL] = + (12.0 ± 3.5)  10 –10 BNL E821 (2004): aexp = (11 659 208.0  5.8) 1010 not yet published not yet published preliminary Teubert

  46. Squark & Gluino Searches @ FNAL General Squarks & gluinos Specific search for light sbottom Heinemann

  47. ATLAS ~ ~ Squark – neutralino1mass difference 5 fb-1 qR qR Sparticle mass measurements @ LHC q • Mass measurements from exclusive cascade decays • Mass differences well measured • Typically limited by detector performance • Of order 1% • Error in overall mass scale • Unknown missing energy • Of order 10% c01 p p c01 q Barr //

  48. Measuring Sparticle Spin @ LHC l- parton-level ATLAS Events spin-0 l+ Charge asymmetry detector-level ATLAS Lepton+jet invariant mass -> Measure spin-1/2 nature of neutralino-2 -> Also can measure scalar nature of slepton ->Success at several distinct points in parameter space Barr //

  49. NLO QCD Calculations Needed for Extracting BSM signals Stirling

  50. Road Map for EWSB Physics Barbieri

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