The ILC - Back to the Energy Frontier

1. The ILC - Back to the Energy Frontier W. Kozanecki (CEA-Saclay)

2. Introduction • World-wide consensus: ICFA, ECFA, ACFA, HEPAP, OECD,… • “…noted the worldwide consensus of the scientific community, which has chosen an e+ - e- linear collider as the next accelerator-based facility to complement and expand on the discoveries that are likely to emerge from the Large Hadron Collider currently being built at CERN. • […It was] agreed that the planning and implementation of such a large, multi-year project should be carried out on a global basis, and should involve consultations among not just scientists, but also representatives of science funding agencies from interested countries....” [ICFA statement, 13 Feb 04] • Remarkable progress toward the realization of an ILC • choice of the technology by the ITRP (Summer 2004) • start of the Global Design Effort • clearer understanding of the essential, mutually supportive relationship of LHC and ILC physics (HEPAP report) • Understatement:Many challenges! • detailed accelerator design, full detector concepts, ever sharper physics arguments • approval & funding strategy - on a worldwide stage

3. Why a TeV Scale e+ e- Accelerator? • Two parallel developments over the past few years (the science) • The precision information from e+e- and n data at present energies 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 needing both pp and e+e- collisions to fully exploit the exciting science expected at the 1 TeV energy scale. • Two parallel developments over the past few years (the technology) • Designs and technology demonstrations have matured on two technical approaches for a ~ 500 GeV e+e- collider that are well matched to our present understanding of the physics: • the TESLA design, based on a superconducting RF linac at 1.3 GHz • the NLC/GLC approach, based on warm RF technology at X-band (11.4 GHz). • By 2002, both designs had come to the stage where the show-stoppers had been eliminated and the feasibility was well-established.

4. e+ e- p p Why LHC andILC ? p = composite particle:unknown s ofi initial-state partons,no polarization of IS partons,parasitic collisions p = strongly interacting:large SM backgrounds,highly selective trigger needed,radiation hard detectors needed e = pointlike particle:known and tunable s of IS particles,polarization of IS particles possible,kinematic contraints can be used e = electroweakly interactinglow SM backgrounds,no trigger needed,detector design driven by precision

5. MHiggs = 120 GeV Number of Events / 1.5 GeV 100 120 140 160 Recoil Mass (GeV) Only possible at the ILC ILC can observe Higgs no matter how it decays! ILC simulation for e+e- Z + Higgs with Z  2 b’s, and Higgs  invisible

6. K. Jakobs (ATLAS), 2005 CERN Summer student lectures are more demanding on the detectors Hadron colliders… pp  HX with H  4  Simulated Higgs production & decay in the CMS detector @ LHC

7. ILC experiments will have the unique ability to make model-independent tests of Higgs couplings to other particles, at the % level of accuracy • LEP e+e- collider • Coupling Strength • to Z boson • e : 0.1% • : 0.1% • : 0.1% • : 0.2% q : 0.1% (PDG values) odel Coupling ∞ particle mass This sensitivity is sufficient to discover extra dimensions, SUSY, sources of CP violation, or other novel phenomena. Standard Model Coupling ∞ particle mass Coupling Strength to Higgs Particle Mass (GeV)

8. LHC/ILC Physics: new particle • LHC experiments find a new heavy particle, Z’ • Able to show that Z’ mediates a new force of nature • This is a great discovery Notice peak is ½ event per bin per fb-1

9. LHC/ILC Physics: new particle • ILC measures couplings of Z’ to find out what it means • If here, related to origin of neutrino masses • If here, related to origin of Higgs • If here, Z’ comes from an extra dimension of space • These are great discoveries!

10. Which Technology to Choose? A major step toward a new international machine required uniting behind one technology, and then working toward a unified global design based on the recommended technology.

11. From a Matrix of Criteria to the Recommendation • The ITRP analyzed the technology choice through studying a matrix having six general categories with specific items under each • the scope and parameters specified by the ILCSC • technical issues • cost issues • schedule issues • physics operation issues • and more general considerations that reflect the impact of the LC on science, technology and society •  Recommendation (announced at ICHEP, Aug ‘04) “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)

12. B. Barrish, GDE Director G. Dugan, (the Americas) B. Foster (Europe) F. Takasaki (Asia) 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.) • GDE structure [America: 16, Europe: 21, Asia: 12] • 3 regional directors • core accelerator physics experts • 3 Conventional Facilities Siting (CFS) experts (1 per region) • 3 costing engineers (1 per region) • 3 communicators (1 per region) • representatives from [LC detector] World Wide Study group

13. GDE Strategy • Primary GDE Goal: • Reference Design Report including costs by the end of 2006 • Intermediate goal (follows from primary) • Definition of a Baseline Configuration by the end of 2005; this • will be designed to during 2006 • will be the basis used for the cost estimate • will evolve into the machine that one will build • Baseline & alternatives: some definitions • Baseline: a forward-looking configuration which one is reasonablyconfident can achieve the required performanceand can be used to give a reasonablyaccurate cost estimate by mid-end 2006 (→ RDR) • Alternative: A technology or concept which may provide a significant cost reduction, increase in performance (or both), but which will not be mature enough to be considered baseline by mid-end 2006

14. Superconducting RF Main Linac ILC Basic Building Blocks & Main Parameters • Ecm adjustable from 200 – 500 GeV • Luminosity ∫Ldt = 500 fb-1 in 4 years • Ability to scan Ecm between 200 and 500 GeV • Energy stability and precision below 0.1% • e- polarization of at least 80% (e+ polarization a serious option) • The machine must be upgradeable to Ecm = 1 TeV

15. LHC Layout from US LC Technology Options Study (March 2004) Design issues The total cost will be a key determining factor in our ability to get the ILC built. Therefore cost optimization of all systems is of primary importance

16. Critical choices: luminosity parameters & gradient The Key Decisions

17. Making Choices – The Tradeoffs Many decisions are interrelated and require input from several WG/GG groups

18. Snowmass 9-cell spec Accelerating gradient: experimental status (single cell)

19. Accelerating gradient: tentative baseline (Snowmass’05) • Cavity shape • baseline: standard TESLA 9-cell • alternatives: low-loss, re-entrant, or superstructure • Gradient specifications

20. Conventional Facilities & Siting • The GDE ILC Design will be done to samples sites in the 3 regions • Milestones • Snowmass 2005 • Complete the Comparative Site-Assessment Matrix Format • Identify Regional Sample Sites for Inclusion into the BCD (Dec ‘05) • North American sample site will be near Fermilab • Japan and Europe are to determine sample sites by the end of 2005 • Complete CFS Portion of the RDR (Dec ‘06) • Outstanding Issues with Direct Impact on CFS Progress that will Require Further Discussion and Resolution • 1 Tunnel vs. 2 Tunnels • Laser Straight vs. Curved or Segmented • Shape and Length of Damping Rings • Shape and Configuration of Sources • 1 vs. 2 Interaction Regions 5 of the 10 most critical design questions may well be influenced by site constraints

21. 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

22. Some of the key topics I had no time to really discuss today ... • Several key acc. issues - Damping Rings, e+ source, Beam Delivery... • The 3 detector concepts (GLD, LCD, SiD) • The growing accelerator R&D effort • in the US • national labs: SLAC, Fermilab, Jefferson Lab... • universities becoming active in specialized, well-chosen areas • in Europe (national F.A.’s + growing EU component) • DESY, CERN, INFN,…. • UK, France, … • in Japan • The rapidly increasing involvement of the experimental community • impressive participation at Snowmass’05 - many new faces ! • Europe has been quite active for more than a decade (TESLA @ DESY) • pushing for detector R&D funding to ramp up - especially in the US • The growing & supportive involvement of gov’t agencies (FALC,...) • The approval & funding strategy in the US

23. Conclusions • Remarkable progress in the past two years toward realizing an international linear collider • important R&D on accelerator systems • definition of parameters for physics • choice of technology • start the global design effort • funding agencies are engaged • Many major hurdles remain before the ILC becomes a reality (funding, site, international organization, and most importantly, a technical design and construction plan) • The time scale for ILC technical project readiness is consistent with proposing a construction project before the end of this decade.

24. The material from this talk came from… • Presentations at the Snowmass’05 Workshop http://alcpg2005.colorado.edu:8080/alcpg2005/program/ • Presentations at the 8th ICFA Seminar (Daegu, Korea, 27 Sep -1 Oct ‘05) by • B. Barrish, GDE Director • R. Heuer, Research Director, DESY • Y. K. Kim, U. of Chicago • P. Oddone, Director, Fermi National Accelerator Laboratory http://chep.knu.ac.kr/ICFA-Seminar/ • “Discovering the Quantum Universe - the Role of Particle Colliders” (DOE / NSF HEPAP Report, 2005) • What I learnt from many of my accelerator friends & colleagues while wandering, over the last 20 years, in, out & back into this exciting field!

25. Backup slides

26. 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 “Quantum Universe”

27. HEPAP report to the EPP 2010 Panel Three physics themes • SOLVING THE MYSTERIES OF MATTER AT THE TeV SCALE • The LHC should discover the Higgs and other new particles. Experiments at the linear collider would then zoom in on these phenomena to discover their secrets. Properties of the Higgs may signal extra dimensions of space or explain the dominance of matter over antimatter. Particle interactions could unveil a universe shaped by supersymmetry. • DETERMINING WHAT DARK MATTER PARTICLES CAN BE PRODUCED IN THE LAB& DISCOVERING THEIR IDENTITY • Most theories contain, at the TeV scale, new massive particles with the right properties to contribute to dark matter. Such particles would first be produced at the LHC. Experiments at the linear collider, in conjunction with dedicated dark matter searches, would then discover whether they actually are dark matter. • CONNECTING THE LAWS OF THE LARGE TO THE LAWS OF THE SMALL • From a vantage point at the TeV scale, the linear collider could function as a telescope to probe far higher energies. This capability offers the potential for discoveries beyond the direct reach of any accelerator that could ever be built.

28. e+ e- Z  qq  jet + jet Event recorded in the ALEPH detector at LEP

29. New forces of nature  new gauge boson Tevatron LHC ILC Events/2GeV 104 103 102 10 1 10-1 qq Z’ e+e- Related to origin of masses Tevatron sensitivity ~1 TeV CDF Preliminary Related to origin of Higgs Vector Coupling Related to Extra dimensions Axial Coupling Mee [GeV] M [GeV] LHC has great discovery potential for multi TeV Z’. Using polarized e+, e- beams, and measuring angular distribution of leptons, ILC can measure Z’ couplings to leptons and discriminate the origins of the new force.

30. LHC ILC e+ e-  102 10 1 10-1 10-2  GN Graviton disappears into the ED Events / 50 GeV / 100 fb-1 Production Rate Collision Energy [GeV] Mee [GeV] Large Extra Dimensions of Space LHC can discover partner towers up to a given energy scale. ILC can identify the size, shape and # of extra dimensions.

31. Dark Matter Mass [GeV] 10 100 1000 Interaction Strengh [cm2] 10-44 1043 10-24 Dark Matter in the Lab Underground experiments (CDMS) may detect Dark Matter candidates (WIMPS) from the galactic halo via impact of colliding DM particle on nuclei. LHC may find DM particles (a SUSY particle) through missing energy analyses. (LHC is the best place to discover many of SUSY particles)

32. Dark Matter Mass from Supersymmetry (GeV) Fraction of Dark Matter Density The ILC can determine its properties with extreme detail, allowing to compute which fraction of the total DM density of the universe it makes.

33. HEPAP LHC / ILC report LHC-ILC synergy (I)

34. LHC-ILC synergy (II)

39. ILC Organization Chart ACFA ICFA ALCSC ILCSC FALC GDE Asia Regional Team European Regional Team American Regional Team

40. Organization following Technology Decision Birth of the GDE & Preparation for Snowmass ’05 • WG1 LET beam dynamics • WG2 Main Linac • WG3a Sources • WG3b Damping Rings • WG4 Beam Delivery • WG5 SCRF Cavity Package • WG6 Communications • GG1 Parameters & Layout • GG2 Instrumentation • GG3 Operations & Reliability • GG4 Cost Engineering • GG5 Conventional Facilities • GG6 Physics Options • WG1 Parms & layout • WG2 Linac • WG3 Injectors • WG4 Beam Delivery • WG5 High Grad. SCRF • WG6 Communications Introduction of Global Groups transition workshop → project

41. LHC Layout from US LC Technology Options Study (March 2004) Design issues

42. How Do 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)

43. Gradient

44. Configuration Parameter Space

45. ILC beam parameter optimization(s) nominally 2  n  