Strategies for Future Acclerators

1. Barry Barish Elba 23-May-06 Strategies for Future Acclerators

2. Strategies for Future Accelerators “Science First” Tools experiments Elba - Strategies for Future Accelerators

3. 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 Elba - Strategies for Future Accelerators

4. 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 Elba - Strategies for Future Accelerators

5. 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. Elba - Strategies for Future Accelerators

6. Why e+e- Collisions ? • elementary particles • well-defined • energy, • angular momentum • uses full COM energy • produces particles democratically • can mostly fully reconstruct events Elba - Strategies for Future Accelerators

7. The Challenge - Developing the Accelerators to Address the Science u Developing Tools Accelerators Detectors The Science HE e+e- ILC / CLIC Elba - Strategies for Future Accelerators

8. 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 Elba - Strategies for Future Accelerators

9. But, not quite high enough energy …. 3.1 GeV Burt Richter Nobel Prize and Discovery Of Charm Particles SPEAR at SLAC Elba - Strategies for Future Accelerators

10. The rich history for e+e- continued as higher energies were achieved … DESY PETRA Collider Elba - Strategies for Future Accelerators

11. Electron Positron CollidersThe Energy Frontier Elba - Strategies for Future Accelerators

12. 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 Elba - Strategies for Future Accelerators

13. 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 Elba - Strategies for Future Accelerators

14. 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. Elba - Strategies for Future Accelerators

15. Is There a New Symmetry in Nature?Supersymmetry Bosons Fermions Virtues of Supersymmetry: • Unification of Forces • The Hierarchy Problem • Dark Matter … Elba - Strategies for Future Accelerators

16. 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 Elba - Strategies for Future Accelerators

17. 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. Elba - Strategies for Future Accelerators

18. 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). Elba - Strategies for Future Accelerators

19. Designing a Linear Collider Superconducting RF Main Linac Elba - Strategies for Future Accelerators

20. 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 Elba - Strategies for Future Accelerators

21. Parametric Approach • A working space - optimize machine for cost/performance Elba - Strategies for Future Accelerators

22. The Baseline Machine (500GeV) ~30 km ML ~10km (G = 31.5MV/m) 20mr RTML ~1.6km 2mr BDS 5km e+ undulator @ 150 GeV (~1.2km) x2 R = 955m E = 5 GeV not to scale Elba - Strategies for Future Accelerators

23. Primary e- source Beam Delivery System IP 250 GeV e- DR Positron Linac 150 GeV 100 GeV Helical Undulator In By-Pass Line Photon Collimators e+ DR Target e- Dump Photon Beam Dump Photon Target Adiabatic Matching Device e+ pre-accelerator ~5GeV Auxiliary e- Source Other Features of the Baseline • Positron Source – Helical Undulator with Polarized beams Elba - Strategies for Future Accelerators

24. Beam Detector Interface Elba - Strategies for Future Accelerators

25. Elements of the ILC R&D Program • R&D in support of the BCD • 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. • Guidance from Change Control Board • Develop a prioritized DETECTOR R&D program aimed at technical developments needed to reach combined design performance goals Elba - Strategies for Future Accelerators

26. 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

27. 2006 From Baseline to a RDR July Dec Jan Frascati Bangalore Vancouver Valencia Freeze Configuration Organize for RDR Review Design/Cost Methodology Review Initial Design / Cost Review Final Design / Cost RDR Document Design and Costing Preliminary RDR Released Elba - Strategies for Future Accelerators

28. Increase diameter beyond X-FEL Increase diameter beyond X-FEL Review 2-phase pipe size and effect of slope ILC Cryomodule Elba - Strategies for Future Accelerators

29. Near Complete Design - Cost Drivers TL • Tunnel Diameter • Both tunnels are 5 meter diameter (Fixed) • 5 meters in Asia & 7.5 meters elsewhere between tunnels (for structural reasons) • 5 meters between tunnels required for shielding Elba - Strategies for Future Accelerators

30. Damping Ring Design Issues Electron Cloud • Ecloud: Threshold of electron cloud, 1.4x1011 m-3. • Ion: Feedback system can suppress for 650 MHz (3ns spacing), • number of bunch in a train 45, and gap between trains 45ns.. Elba - Strategies for Future Accelerators

31. Accelerator Physics Challenges • Develop High Gradient Superconducting RF systems • Requires efficient RF systems, capable of accelerating high power beams (~MW) with small beam spots(~nm). • Achieving nm scale beam spots • Requires generating high intensity beams of electrons and positrons • Damping the beams to ultra-low emittance in damping rings • Transporting the beams to the collision point without significant emittance growth or uncontrolled beam jitter • Cleanly dumping the used beams. • Reaching Luminosity Requirements • Designs satisfy the luminosity goals in simulations • A number of challenging problems in accelerator physics and technology must be solved, however. Elba - Strategies for Future Accelerators

32. Detectors for the ILC • Large Scale 4p detectors with solenoidal magnetic fields. • In order to take full advantage of the ILC ability to reconstruct, need to improve resolutions, tracking, etc by factor of two or three • New techniques in calorimetry, granularity of readout etc being developed Elba - Strategies for Future Accelerators

33. Conclusions • We have determined a number of very fundamental physics questions to answer, like …. • What determines mass? • What is the dark matter? • Are there new symmetries in nature? • What explains the baryon asymmetry? • Are the forces of nature unified • We are developing the tools to answer these questions and discover new ones • Neutrino Physics • Large Hadron Collider • International Linear Collider • Hopefully, LHC will validate this approach Elba - Strategies for Future Accelerators