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From the Tevatron to the LHC Coseners House, April 24-25, 2004 Morning Prayer John Ellis

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Open Questions beyond the Standard Model What is the origin of particle masses? due to a Higgs boson? + other physics? solution at energy < 1 TeV (1000 GeV) Why so many types of matter particles? matter-antimatter difference? Unification of the fundamental forces? at very high energy ~ 10 16 GeV? probe directly via neutrino physics, indirectly via masses, couplings Quantum theory of gravity? extra space-time dimensions? All these issues tackled by the LHC (Tevatron)

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Electroweak Symmetry Breaking

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The Electroweak Vacuum Generating particle masses requires breaking gauge symmetry: m W,Z =/= 0 =/= 0 m W 2 = m Z 2 cos 2 θ W => I = ½ I = ½ also needed for fermion masses What is X? Elementary or Composite?

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Elementary Higgs or Composite? Higgs field: =/= 0 Problems with loops Fermion-antifermion condensate Just like QCD, BCS superconductivity Top-antitop condensate? needed m t > 200 GeV New technicolour force? inconsistent with precision electroweak data? Cut-off Λ ~ 1 TeV with Supersymmetry? Cutoff Λ = 10 TeV

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Searches for the Higgs Boson Indirect: Precision electroweak measurements at LEP, SLC, etc Predicted successfully m t = 160 – 180 GeV Sensitive to mass of Higgs boson m H < 200 GeV ? Direct: LEP Searches for e + e - -> Z + H Hint seen in late 2000 now < 2 σ Current Limit: m H > 114.4 GeV

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Waiting for the Higgs boson Higgs probability distribution: combining direct, indirect information m H > 114.4 GeV How soon will the Higgs be found? …

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Theorists getting Cold Feet 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?

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Heretical Interpretation of EW Data Do all the data tell the same story? e.g., A L vs A H What attitude towards LEP, NuTeV? What most of us think

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Higgs + Higher-Order Operators Precision EW data suggest they are small: why? But conspiracies are possible: m H could be large, even if believe EW data …? Do not discard possibility of heavy Higgs Corridor to heavy Higgs?

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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 Not as complete as susy: more physics > 10 TeV M T < 2 TeV (m h / 200 GeV) 2 M W < 6 TeV (m h / 200 GeV) 2 M H++ < 10 TeV

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Generic Little Higgs Spectrum Loop cancellation mechanisms SupersymmetryLittle Higgs

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Higgsless Models Four-dimensional versions: Strong WW scattering @ TeV, incompatible with precision data? Break EW symmetry by boundary conditions in extra dimension: delay strong WW scattering to ~ 10 TeV? Kaluza-Klein modes: m KK > 300 GeV? compatibility with precision data? Warped extra dimension + brane kinetic terms? Lightest KK mode @ 300 GeV, strong WW @ 6-7 TeV

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Tevatron & LHC

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Updated Estimate of Tevatron Higgs Reach (June 2003)

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Updated Tevatron Luminosity Projections

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The Large Hadron Collider (LHC) Proton- Proton Collider 7 TeV +7 TeV Luminosity = 10 34 cm -2 sec -1 Primary targets: Origin of mass Nature of Dark Matter Primordial Plasma Matter vs Antimatter

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LHC Progress `Dashboard

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The First Direct Exploration of the TeV Scale … Why is this interesting? Any new energy range takes us deeper inside matter, but also … Several reasons to expect new physics: Origin of particle masses Stabilization of gauge hierarchy Unification of couplings Dark matter g – 2 of muon

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The Physics Scope of the LHC Bread-and-butter physics Δm = 15 MeV Δm = 1 GeV Interesting cross sections W top Higgs Susy

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Higgs Production at the LHC A la recherche du Higgs perdu … … not far away? Combining direct, Indirect information

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Some Sample Higgs Signals ttH bbH γγ ZZ* -> llll

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Measuring Higgs Self-Coupling Heavier Higgs possible @ SLHCLight Higgs @ low-energy LC LHC-LC report

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Sensitivity to Strong WW scattering @ LHC @ 800 GeV LC LHC-LC report

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Measuring WW Resonance Form factor measurements @ 500 GeV LC Resonance parameters @ LHC Resonance parameters @ 500 GeV LC LHC-LC report

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Constraining Triple-Gauge Coupling

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Other Physics @ EW Scale

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Why Supersymmetry (Susy)? Hierarchy problem: why is m W << m P ? (m P ~ 10 19 GeV is scale of gravity) Alternatively, why is G F = 1/ m W 2 >> G N = 1/m P 2 ? Or, why is V Coulomb >> V Newton ? e 2 >> G m 2 = m 2 / m P 2 Set by hand? What about loop corrections? δm H,W 2 = O(α/π) Λ 2 Cancel boson loops fermions Need | m B 2 – m F 2 | < 1 TeV 2

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Other Reasons to like Susy It enables the gauge couplings to unify It stabilizes the Higgs potential for low masses Approved by Fabiola Gianotti

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Constraints on Supersymmetry Absence of sparticles at LEP, Tevatron selectron, chargino > 100 GeV squarks, gluino > 250 GeV Indirect constraints Higgs > 114 GeV, b -> s γ Density of dark matter lightest sparticle χ: WMAP: 0.094 < Ω χ h 2 < 0.124 g μ - 2

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Current Constraints on CMSSM WMAP constraint on relic density Excluded because stau LSP Excluded by b s gamma Excluded (?) by latest g - 2 Latest CDF/D0 top mass Focus-point region above 7 TeV for m t = 178 GeV JE, Olive, Santoso, Spanos

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Current Constraints on CMSSM Impact of Higgs constraint reduced if larger m t Focus-point region far up Different tan β sign of μ JE, Olive, Santoso, Spanos

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Density below WMAP limit Decays do not affect BBN/CMB agreement Different Regions of Sparticle Parameter Space if Gravitino LSP Different Gravitino masses JE, Olive, Santoso, Spanos

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500 (1000) GeV LC covers part of space

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Supersymmetry Searches at LHC `Typical supersymmetric Event at the LHC LHC reach in supersymmetric parameter space

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Observability of Lightest CMSSM Higgs Boson Cross section comparable to SM Higgs JE, Heinemeyer, Olive, Weiglein

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Heavier MSSM Higgs Bosons Observability @ LHC LHC-LC report

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CP Violation in the MSSM? Assuming universality for the soft susy- breaking parameters Two possible sources: Phase in trilinear term A: φ A Phase in gluino mass: φ 3 Loop effects on MSSM Higgs bosons CP-violating mixing: h, H A

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Observability @ LEP & LHC Some uncovered regions of parameter space Carena, JE, Mrenna, Pilaftsis, Wagner Assuming common value of φ A, φ 3

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Cross Sections across Mixed Higgs Peaks JE, Lee, Pilaftsis φ A = 90, φ 3 = -90, -10 Diagrams Kinematics

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CP-Violating Asymmetries Rather smallCould be large! JE, Lee, Pilaftsis

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Examples of Integrated Asymmetries Could be large! JE, Lee, Pilaftsis

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Supersymmetric Benchmark Studies Specific benchmark Points along WMAP lines Lines in susy space allowed by accelerators, WMAP data Sparticle Detectability @ LHC along one WMAP line LHC enables calculation of relic density at a benchmark point Battaglia, De Roeck, JE, Gianotti, Olive, Pape

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LHC almost `guaranteed to discover supersymmetry if it is relevant to the mass problem LHC and LC Scapabilities LC oberves complementary sparticles Battaglia, De Roeck, JE, Gianotti, Olive, Pape

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Example of Benchmark Point Spectrum of Benchmark SPS1a ~ Point B of Battaglia et al Several sparticles at 500 GeV LC, more at 1000 GeV, some need higher E LHC-LC report

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Examples of Sparticle Measurements Spectrum edges @ LHC Threshold excitation @ LC Spectra @ LC LHC-LC report

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Mass Measurements @ Benchmark B = SPS1a Fit to CMSSM parameters LHC-LC report

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Supersymmetric Benchmark Studies Specific benchmark Points along WMAP lines Lines in susy space allowed by accelerators, WMAP data Sparticle detectability Along one WMAP line Calculation of relic density at a benchmark point Battaglia, De Roeck, JE, Gianotti, Olive, Pape

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JE, Olive, Santoso How `Likely are Large Sparticle Masses? Fine-tuning of EW scaleFine-tuning of relic density Larger masses require more fine-tuning: but how much is too much?

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If not supersymmetry, what ? Extra Dimensions ? - Suggested by Kaluza and Klein to unify gravity and electromagnetism - Required for consistency of string theory - Could help unify strong, weak and electromagnetic forces with gravity if >> l P - Could be origin of supersymmetry breaking - Enable reformulation of the hierarchy problem Reformulated

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Sequence of KK Resonances? In Randall-Sundrum model S 1 /Z 2 orbifold version @ LC Possible spectrum @ LHC Sensitivity in contact-interaction regime LHC-LC report

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Scenario with Universal Extra D Spectrum like supersymmetry: More degenerate Lightest KK particle stable: dark matter? Distinguish from susy via LC cross sections LHC-LC report

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`Constrained Standard Model Break supersymmetry by boundary conditions in extra dimension If top quark not localized, 1-parameter potential: m H = 130 GeV, 1/R ~ 400 GeV Relaxed if top quark partially localized LSP is stop Barbieri

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And if there are large extra dimensions & gravity becomes strong at the TeV scale Black Hole Production at LHC? Multiple jets, Leptons from Hawking Radiation

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The Reach of the LHC for New High-Mass Physics

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