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

2. Elba - Strategies for Future Accelerators2 Strategies for Future Accelerators Tools “Science First” experiments

3. 23-May-06Elba - Strategies for Future Accelerators3 Particle Physics 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

4. 23-May-06Elba - Strategies for Future Accelerators4 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

5. 23-May-06Elba - Strategies for Future Accelerators5 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.

6. 23-May-06Elba - Strategies for Future Accelerators6 Why e + e - Collisions ? elementary particles well-defined –energy, –angular momentum uses full COM energy produces particles democratically can mostly fully reconstruct events

7. 23-May-06Elba - Strategies for Future Accelerators7 u The Science Developing Tools Accelerators Detectors HE e+e- The Challenge - Developing the Accelerators to Address the Science ILC / CLIC

8. 23-May-06Elba - Strategies for Future Accelerators8 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

9. 23-May-06Elba - Strategies for Future Accelerators9 But, not quite high enough energy …. Discovery Of Charm Particles and 3.1 GeV Burt Richter Nobel Prize SPEAR at SLAC

10. 23-May-06Elba - Strategies for Future Accelerators10 The rich history for e + e - continued as higher energies were achieved … DESY PETRA Collider

11. 23-May-06Elba - Strategies for Future Accelerators11 Electron Positron Colliders The Energy Frontier

12. 23-May-06Elba - Strategies for Future Accelerators12 The linear collider will measure the spin of any Higgs it can produce by measuring the energy dependence from threshold How do you know you have discovered the Higgs ? Measure the quantum numbers. The Higgs must have spin zero !

13. 23-May-06Elba - Strategies for Future Accelerators13 What can we learn from the Higgs? 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 Precision measurements of Higgs coupling can reveal extra dimensions in nature

14. 23-May-06Elba - Strategies for Future Accelerators14 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. Linear collider Direct production from extra dimensions ?

15. 23-May-06Elba - Strategies for Future Accelerators15 BosonsFermions Virtues of Supersymmetry: –Unification of Forces –The Hierarchy Problem –Dark Matter … Is There a New Symmetry in Nature? Supersymmetry

16. 23-May-06Elba - Strategies for Future Accelerators16 Parameters for the ILC E cm 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

17. 23-May-06Elba - Strategies for Future Accelerators17 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.

18. 23-May-06Elba - Strategies for Future Accelerators18 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).

19. 23-May-06Elba - Strategies for Future Accelerators19 Designing a Linear Collider Superconducting RF Main Linac

20. 23-May-06Elba - Strategies for Future Accelerators20 rf bands: L-band (TESLA)1.3 GHz  = 3.7 cm S-band (SLAC linac) 2.856 GHz1.7 cm C-band (JLC-C)5.7 GHz0.95 cm X-band (NLC/GLC)11.4 GHz0.42 cm (CLIC)25-30 GHz0.2 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 Specific Machine Realizations Frequency dictates many of the design issues for LC RF Bands

21. 23-May-06Elba - Strategies for Future Accelerators21 Parametric Approach A working space - optimize machine for cost/performance

22. 23-May-06Elba - Strategies for Future Accelerators22 The Baseline Machine (500GeV) not to scale ~30 km e+ undulator @ 150 GeV (~1.2km) x2 R = 955m E = 5 GeV RTML ~1.6km ML ~10km (G = 31.5MV/m) 20mr 2mr BDS 5km

23. 23-May-06Elba - Strategies for Future Accelerators23 Other Features of the Baseline Positron Source – Helical Undulator with Polarized beams Primary e - source e - DR Target e - Dump Photon Beam Dump e + DR Auxiliary e - Source Photon Collimators Adiabatic Matching Device e + pre- accelerator ~5GeV 150 GeV100 GeV Helical Undulator In By-Pass Line Photon Target 250 GeV Positron Linac IP Beam Delivery System

24. 23-May-06Elba - Strategies for Future Accelerators24 Beam Detector Interface

25. 23-May-06Elba - Strategies for Future Accelerators25 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

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

27. 23-May-06Elba - Strategies for Future Accelerators27 From Baseline to a RDR Jan JulyDec 2006 Freeze Configuration Organize for RDR Bangalore Review Design/Cost Methodology Review Initial Design / Cost Review Final Design / Cost RDR Document Design and CostingPreliminary RDR Released FrascatiVancouverValencia

28. 23-May-06Elba - Strategies for Future Accelerators28 Increase diameter beyond X-FEL Increase diameter beyond X-FEL Review 2-phase pipe size and effect of slope ILC Cryomodule

29. 23-May-06Elba - Strategies for Future Accelerators29 Tunnel Diameter Both tunnels are 5 meter diameter (Fixed) Both tunnels are 5 meter diameter (Fixed) 5 meters in Asia & 7.5 meters elsewhere between tunnels (for structural reasons) 5 meters in Asia & 7.5 meters elsewhere between tunnels (for structural reasons) 5 meters between tunnels required for shielding 5 meters between tunnels required for shielding Near Complete Design - Cost Drivers TL

30. 23-May-06Elba - Strategies for Future Accelerators30 Ecloud: Threshold of electron cloud, 1.4x10 11 m -3. Ion: Feedback system can suppress for 650 MHz (3ns spacing), number of bunch in a train 45, and gap between trains 45ns.. Damping Ring Design Issues Electron Cloud

31. 23-May-06Elba - Strategies for Future Accelerators31 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.

32. 23-May-06Elba - Strategies for Future Accelerators32 Large Scale 4  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 Detectors for the ILC

33. 23-May-06Elba - Strategies for Future Accelerators33 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