The International Linear Collider

1. Barry Barish ANL Colloquium 3-Jan-06 The International Linear Collider

2. Particle PhysicsInquiry Based Science • Are there undiscovered principles of nature: New symmetries, new physical laws? • How can we solve the mystery of dark energy? • Are there extra dimensions of space? • Do all the forces become one? • Why are there so many kinds of particles? • What is dark matter? How can we make it in the laboratory? • What are neutrinos telling us? • How did the universe come to be? • What happened to the antimatter? from the Quantum Universe ANL Director's Colloquium

3. Answering the QuestionsThree 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 ANL Director's Colloquium

4. Neutrinos – Many Questions • Why are neutrino masses so small ? • Are the neutrinos their own antiparticles? • What is the separation and ordering of the masses of the neutrinos? • Neutrinos contribution to the dark matter? • CP violation in neutrinos, leptogenesis, possible role in the early universe and in understanding the particle antiparticle asymmetry in nature? ANL Director's Colloquium

5. Neutrinos – The Future • Long baseline neutrino experiments – Create neutrinos at an accelerator or reactor and study at long distance when they have oscillated from one type to another. MINOS Opera ANL Director's Colloquium

6. Why a TeV Scale e+e- Accelerator? • Two parallel developments over the past few years (the science & the technology) • The precision information from LEP and other data have pointed to a low mass Higgs; Understanding electroweak symmetry breaking, whether supersymmetry or an alternative, will require precision measurements. • There are strong arguments for the complementarity between a ~0.5-1.0 TeV ILC and the LHC science. ANL Director's Colloquium

7. Electroweak Precision Measurements What causes mass?? The mechanism – Higgs or alternative appears around the corner ANL Director's Colloquium

8. Accelerators and the Energy Frontier Large Hadron Collider CERN – Geneva Switzerland ANL Director's Colloquium

9. The Higgs Field Source of mass to all other particles LHC and the Energy FrontierSource of Particle Mass Discover the Higgs The Higgs Field LEP fb-1 FNAL or variants or ??? ANL Director's Colloquium

10. LHC and the Energy FrontierA New Force in Nature Discover a new heavy particle, Z’ Can show by measuring the couplings with the ILC how it relates to other particles and forces ANL Director's Colloquium

11. This led to higher energy machines:Electron-Positron Colliders Bruno Touschek built the first successful electron-positron collider at Frascati, Italy (1960) Eventually, went up to 3 GeV ADA ANL Director's Colloquium

12. But, not quite high enough energy …. 3.1 GeV Burt Richter Nobel Prize and Discovery Of Charm Particles SPEAR at SLAC ANL Director's Colloquium

13. The rich history for e+e- continued as higher energies were achieved … DESY PETRA Collider ANL Director's Colloquium

14. Electron Positron CollidersThe Energy Frontier ANL Director's Colloquium

15. Why e+e- Collisions ? • elementary particles • well-defined • energy, • angular momentum • uses full COM energy • produces particles democratically • can mostly fully reconstruct events ANL Director's Colloquium

16. 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 ANL Director's Colloquium

17. What can we learn from the Higgs? Precision measurements of Higgs coupling can reveal extra dimensions in nature • Straight blue line gives the standard model predictions. • Range of predictions in models with extra dimensions -- yellow band, (at most 30% below the Standard Model • The red error bars indicate the level of precision attainable at the ILC for each particle ANL Director's Colloquium

18. Linear collider Direct production from extra dimensions ? 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. ANL Director's Colloquium

19. Is There a New Symmetry in Nature?Supersymmetry Bosons Fermions Virtues of Supersymmetry: • Unification of Forces • The Hierarchy Problem • Dark Matter … ANL Director's Colloquium

20. 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 ANL Director's Colloquium

21. A TeV Scale e+e- Accelerator? • Two parallel developments over the past few years (the science & the technology) • Two alternate designs -- “warm” and “cold” had come to the stage where the show stoppers had been eliminated and the concepts were well understood. • A major step toward a new international machine requires uniting behind one technology, and then make a unified global design based on the recommended technology. ANL Director's Colloquium

22. The JLC-X and NLC essentially a unified single design with common parameters • The main linacs based on 11.4 GHz, room temperature copper technology. GLC GLC/NLC Concept ANL Director's Colloquium

23. TESLA Concept • The main linacs based on 1.3 GHz superconducting technology operating at 2 K. • The cryoplant, is of a size comparable to that of the LHC, consisting of seven subsystems strung along the machines every 5 km. ANL Director's Colloquium

24. Drive Beam CLIC Concept The main linac rf power is produced by decelerating a high-current (150 A) low-energy (2.1 GeV) drive beam Nominal accelerating gradient of 150 MV/m GOAL Proof of concept ~2010 Main Accelerator ANL Director's Colloquium

25. 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 ANL Director's Colloquium

26. The ITRP Recommendation • We recommend that the linear collider be based on superconducting rf technology • This recommendation is made with the understanding that we are recommending a technology, not a design. We expect the final design to be developed by a team drawn from the combined warm and cold linear collider communities, taking full advantage of the experience and expertise of both(from the Executive Summary). ANL Director's Colloquium

27. The Community Self-Organized Nov 13-15, 2004 ANL Director's Colloquium

28. Global Design Effort (GDE) • February 2005, at TRIUMF, ILCSC and ICFA unanimously endorsed the search committee choice for GDE Director • On March 18, 2005 Barry Barish officially accepted the position at the opening of LCWS 05 meeting at Stanford ANL Director's Colloquium

29. Global Design Effort • The Mission of the GDE • Produce a design for the ILC that includes a detailed design concept, performance assessments, reliable international costing, an industrialization plan , siting analysis, as well as detector concepts and scope. • Coordinate worldwide prioritized proposal driven R & D efforts (to demonstrate and improve the performance, reduce the costs, attain the required reliability, etc.) ANL Director's Colloquium

30. 2005 2006 2007 2008 2009 2010 CLIC Global Design Effort Project LHC Physics Baseline configuration Reference Design The GDE Plan and Schedule Technical Design ILC R&D Program Expression of Interest to Host International Mgmt

31. GDE Begins at Snowmass 670 Scientists attended two week workshop at Snowmass GDE Members Americas 22 Europe 24 Asia 16 ANL Director's Colloquium

32. Designing a Linear Collider Superconducting RF Main Linac ANL Director's Colloquium

33. WG1 LET bdyn. WG2 Main Linac WG3a Sources WG3b DR WG4 BDS WG5 Cavity GG1 Parameters GG2 Instrumentation GG3 Operations & Reliability GG4 Cost & Engineering GG5 Conventional Facilities GG6 Physics Options GDE Organization for Snowmass Technical sub-system Working Groups Provide input Global Group ANL Director's Colloquium

34. Specific Machine Realizations • rf bands: • L-band (TESLA) 1.3 GHz l = 3.7 cm • S-band (SLAC linac) 2.856 GHz 1.7 cm • C-band (JLC-C) 5.7 GHz 0.95 cm • X-band (NLC/GLC) 11.4 GHz 0.42 cm • (CLIC) 25-30 GHz 0.2 cm • Accelerating structure size is dictated by wavelength of the rf accelerating wave. Wakefields related to structure size; thus so is the difficulty in controlling emittance growth and final luminosity. • Bunch spacing, train length related to rf frequency • Damping ring design depends on bunch length, hence frequency RF Bands Frequency dictates many of the design issues for LC ANL Director's Colloquium

35. Design Approach • Create a baseline configuration for the machine • Document a concept for ILC machine with a complete layout, parameters etc. defined by the end of 2005 • Make forward looking choices, consistent with attaining performance goals, and understood well enough to do a conceptual design and reliable costing by end of 2006. • Technical and cost considerations will be an integral part in making these choices. • Baseline will be put under “configuration control,” with a defined process for changes to the baseline. • A reference design will be carried out in 2006. I am proposing we use a “parametric” design and costing approach. • Technical performance and physics performance will be evaluated for the reference design ANL Director's Colloquium

36. The Key Decisions Critical choices: luminosity parameters & gradient ANL Director's Colloquium

37. Making Choices – The Tradeoffs Many decisions are interrelated and require input from several WG/GG groups ANL Director's Colloquium

38. ILC Baseline Configuration • Configuration for 500 GeV machine with expandability to 1 TeV • Some details – locations of low energy acceleration; crossing angles are not indicated in this cartoon. ANL Director's Colloquium

39. Cost Breakdown by Subsystem Civil SCRF Linac ANL Director's Colloquium

40. Approach to ILC R&D Program • Proposal-driven R&D in support of the baseline design. • Technical developments, demonstration experiments, industrialization, etc. • Proposal-driven R&D in support of alternatives to the baseline • Proposals for potential improvements to the baseline, resources required, time scale, etc. • Develop a prioritized DETECTOR R&D program aimed at technical developments needed to reach combined design performance goals ANL Director's Colloquium

41. TESLA Cavity ~1m 9-cell 1.3GHz Niobium Cavity Reference design: has not been modified in 10 years ANL Director's Colloquium

42. How Costs Scale with Gradient? 35MV/m is close to optimum Japanese are still pushing for 40-45MV/m 30 MV/m would give safety margin Relative Cost Gradient MV/m C. Adolphsen (SLAC) ANL Director's Colloquium

43. Superconducting RF Cavities High Gradient Accelerator 35 MV/meter -- 40 km linear collider ANL Director's Colloquium

44. Improved Cavity Shapes ANL Director's Colloquium

45. Improved Fabrication ANL Director's Colloquium

46. Improved ProcessingElectropolishing Chemical Polish Electro Polish ANL Director's Colloquium

47. Electro-polishing (Improve surface quality -- pioneering work done at KEK) BCP EP • Several single cell cavities at g > 40 MV/m • 4 nine-cell cavities at ~35 MV/m, one at 40 MV/m • Theoretical Limit 50 MV/m ANL Director's Colloquium

48. Gradient Results from KEK-DESY collaboration must reduce spread (need more statistics) single-cell measurements (in nine-cell cavities) ANL Director's Colloquium

49. Baseline Gradient ANL Director's Colloquium

50. Large Grain Single Crystal Nb Material ANL Director's Colloquium