The Next Great Particle Accelerator A TeV Scale l +l _ Linear Collider Barry Barish Caltech JLab Colloquium 11-Sept-08 Particle Physics An Inquiry Based Science 1. Are there undiscovered principles of nature: New symmetries, new physical laws? 2. How can we solve the mystery of dark energy? 3. Are there extra dimensions of space? 4. Do all the forces become one? 5. Why are there so many kinds of particles? 6. What is dark matter? How can we make it in the laboratory? 7. What are neutrinos telling us? 8. How did the universe come to be? 9. What happened to the antimatter? from the Quantum Universe 11-Sept-08 The International Linear Collider 2 JLab Colloquium Answering the Questions Three Complementary Probes + … • Neutrinos as a Probe – Particle physics and astrophysics using a weakly interacting probe • High Energy Proton Proton Colliders – Opening up a new energy frontier ( ~ 1 TeV scale) • High Energy Electron Positron Colliders – Precision Physics at the new energy frontier • Increasing connections to Astrophysics/Cosmology 11-Sept-08 The International Linear Collider 3 JLab Colloquium Exploring the Terascale the tools • The LHC – It will lead the way and has large reach – Quark-quark, quark-gluon and gluon-gluon collisions at 0.5 - 5 TeV – Broadband initial state • The ILC – A second view with high precision – Electron-positron collisions with fixed energies, adjustable between 0.1 and 1.0 TeV – Well defined initial state • Together, these are our tools for the terascale 11-Sept-08 The International Linear Collider 4 JLab Colloquium Electron-Positron Colliders Bruno Touschek built the first ADA successful electron-positron collider at Frascati, Italy (1960) Eventually, went up to 3 GeV 11-Sept-08 The International Linear Collider 5 JLab Colloquium But, not quite high enough energy …. 3.1 GeV Burt Richter Nobel Prize and Discovery Of SPEAR at SLAC Charm Particles 11-Sept-08 The International Linear Collider 6 JLab Colloquium The rich history for e+e- continued as higher energies were achieved … DESY PETRA Collider 11-Sept-08 The International Linear Collider 7 JLab Colloquium And also at LEP, where the stage has been set for the terascale Winter 2003 What causes mass ?? 6 theory uncertainty (5) The mechanism – Higgs had = 0.02761 0.00036 or alternative appears 0.02747 0.00012 around the corner 4 Without NuTeV 2 Excluded Preliminary 0 20 100 400 mH GeV 11-Sept-08 The International Linear Collider 8 JLab Colloquium Three Generations of e+e- Colliders The Energy Frontier ILC LEP PETRA Fourth Generation? ENERGY SPEAR 1970 YEAR 2020 11-Sept-08 The International Linear Collider 9 JLab Colloquium Possible TeV Scale Lepton Colliders ILC < 1 TeV Technically possible ILC ~ 2020 + QUAD Drive beam - 95 A, 300 ns QUAD POWER EXTRACTION from 2.4 GeV to 240 MeV STRUCTURE CLIC CLIC < 3 TeV ACCELERATING STRUCTURES Feasibility? Main beam – 1 A, 200 ns from 9 GeV to 1.5 TeV BPM Longer timescale Muon Collider Much R&D Needed Muon Collider • Neutrino Factory R&D + < 4 TeV • bunch merging • much more cooling FEASIBILITY?? • etc Much longer timescale 11-Sept-08 The International Linear Collider 10 JLab Colloquium Why e+e- Collisions ? • elementary particles • well-defined – energy, – angular momentum • uses full COM energy • produces particles democratically • can mostly fully reconstruct events 11-Sept-08 The International Linear Collider 11 JLab Colloquium LHC: Low mass Higgs: H gg 2 MH < 150 GeV/c . Rare decay channel: BR ~ 10-3 . Requires excellent electromagnetic calorimeter performance . acceptance, energy and angle resolution, . g/jet and g/p0 separation . Motivation for LAr/PbWO4 calorimeters for CMS . Resolution at 100 GeV: 1 GeV . Background large: S/B 1:20, but can estimate from non signal areas CMS 11-Sept-08 The International Linear Collider 12 JLab Colloquium ILC: Precision Higgs physics . Model-independent Studies • mass • absolute branching ratios • total width • spin • top Yukawa coupling • self coupling . Precision Measurements Garcia-Abia et al 11-Sept-08 The International Linear Collider 13 JLab Colloquium How do you know you have discovered the Higgs ? Measure the quantum numbers. The Higgs must have spin zero ! The linear collider will measure the spin of any Higgs it can produce by measuring the energy dependence from threshold 11-Sept-08 The International Linear Collider 14 JLab Colloquium What can we learn from the Higgs? Precision measurements of Higgs coupling Higgs Coupling strength is proportional to Mass 11-Sept-08 The International Linear Collider 15 JLab Colloquium e+e- : Studying the Higgs determine the underlying model SM 2HDM/MSSM Yamashita et al Zivkovic et al 11-Sept-08 The International Linear Collider 16 JLab Colloquium Top Quark Measurements Threshold scan provides mass measurement Theory (NNLL) controls mt(MS) to 100 MeV 11-Sept-08 The International Linear Collider 17 JLab Colloquium Top Quark Measurements Bounds on axial ttbarZ and left handed tbW for LHC and ILC compared to deviations in various models 11-Sept-08 The International Linear Collider 18 JLab Colloquium Supersymmetry Supersymmetric Partner ~ u c t H u~ c~ t~ H~ ~ ~ ~ ~ d s b g H d s b g H~ ~ ~ ~ ~ e W e W ~ e Z e~ ~ ~ Z Spin Spin Spin Spin Spin Spin 1/2 1 0 0 1/2 1/2 11-Sept-08 The International Linear Collider 19 JLab Colloquium Supersymmetry at ILC e+e- production crosssections - Measure quantum numbers - Is it MSSM, NMSSM, …? - How is it broken? ILC can answer these questions! - tunable energy - polarized beams 11-Sept-08 The International Linear Collider 20 JLab Colloquium ILC Supersymmetry Two methods to obtain absolute sparticle masses: Kinematic Threshold: In the continuum Freitas Martyn Determine SUSY Minimum and maximum determines parameters without model masses of primary slepton and assumptions secondary neutralino/chargino 11-Sept-08 The International Linear Collider 21 JLab Colloquium Supersymmetry quark and lepton unification Do Quarks and Leptons also Unify? 1015 TeV •Predicted in most models •Can be tested at the ILC 11-Sept-08 The International Linear Collider 22 JLab Colloquium Direct production from extra dimensions ? Linear collider New space-time dimensions can be mapped by studying the emission of gravitons into the extra dimensions, together with a photon or jets emitted into the normal dimensions. 11-Sept-08 The International Linear Collider 23 JLab Colloquium Why Linear? • Circular Machine R Synchrotron – E ~ (E4 /m4 R) R Radiation – Cost ~ a R + b E m,E ~ a R + b (E4 /m4 R) – Optimization : R ~ E2 Cost ~ c E2 Circular – Cost (linear) ~ a L Collider Linear Collider – where L ~ E cost ~ 200 GeV Energy 11-Sept-08 The International Linear Collider 24 JLab Colloquium How the physics defines the ILC 11-Sept-08 The International Linear Collider 25 JLab Colloquium Parameters for the ILC • Ecm adjustable from 200 – 500 GeV • Luminosity ∫Ldt = 500 fb-1 in 4 years • Ability to scan between 200 and 500 GeV • Energy stability and precision below 0.1% • Electron polarization of at least 80% • The machine must be upgradeable to 1 TeV 11-Sept-08 The International Linear Collider 26 JLab Colloquium ILC – Underlying Technology • Room temperature copper structures OR • Superconducting RF cavities 11-Sept-08 The International Linear Collider 27 JLab Colloquium SCRF Technology Recommendation • The recommendation of ITRP was presented to ILCSC & ICFA on August 19, 2004 in a joint meeting in Beijing. • ICFA unanimously endorsed the ITRP‟s recommendation on August 20, 2004 11-Sept-08 The International Linear Collider 28 JLab Colloquium Superconducting RF Technology • Forward looking technology for the next generation of particle accelerators: particle physics; nuclear physics; materials; medicine • The ILC R&D is leading the way Superconducting RF technology – high gradients; low noise; precision optics 11-Sept-08 The International Linear Collider 29 JLab Colloquium Designing a Linear Collider pre-accelerator few GeV source KeV damping extraction ring few GeV 250-500 GeV & dump few GeV final focus IP bunch main linac compressor collimation Superconducting RF Main Linac 11-Sept-08 The International Linear Collider 30 JLab Colloquium Luminosity & Beam Size 2 nb N frep L H D 2 x y • frep * nb tends to be low in a linear collider 10 L frep [Hz] nb N [10 ] x [ m] y [ m] ILC 2x1034 5 3000 2 0.5 0.005 SLC 2x1030 120 1 4 1.5 0.5 LEP2 5x1031 10,000 8 30 240 4 PEP-II 1x1034 140,000 1700 6 155 4 • Achieve luminosity with spot size and bunch charge 11-Sept-08 The International Linear Collider 31 JLab Colloquium Achieving High Luminosity • Low emittance machine optics • Contain emittance growth • Squeeze the beam as small as possible e- e+ ~ 5 nm Interaction Point (IP) 11-Sept-08 The International Linear Collider 32 JLab Colloquium ILC Reference Design – 11km SC linacs operating at 31.5 MV/m for 500 GeV – Centralized injector • Circular damping rings for electrons and positrons • Undulator-based positron source – Single IR with 14 mrad crossing angle – Dual tunnel configuration for safety and availability Reference Design – Feb 2007 11Documented-Sept-08 in TheReference International Linear Collider Design Report 33 JLab Colloquium RDR Design Parameters Max. Center-of-mass energy 500 GeV Peak Luminosity ~2x1034 1/cm2s Beam Current 9.0 mA Repetition rate 5 Hz Average accelerating gradient 31.5 MV/m Beam pulse length 0.95 ms Total Site Length 31 km Total AC Power Consumption ~230 MW 11-Sept-08 The International Linear Collider 34 JLab Colloquium RDR Cost Estimating • “Value” Costing System: International costing for International Project – Provides basic agreed to “value” costs – Provides estimate of “explicit” labor (man-hr)] • Based on a call for world-wide tender: lowest reasonable price for required quality • Classes of items in cost estimate: – Site-Specific: separate estimate for each sample site – Conventional: global capability (single world est.) – High Tech: cavities, cryomodules (regional estimates) 11-Sept-08 The International Linear Collider 35 JLab Colloquium RDR Design & “Value” Costs The reference design was “frozen” Summary as of 1-Dec-06 for the purpose of producing the RDR, including costs.