1. Linear e + e - collider case Stretching the loops 22 May 20121Nikhef strategy: LC (SdJ) Contents: Why an e + e - linear collider Physics case Technology case Funding & Politics

2. Why a linear e + e - collider e + e - : Collide “elementary” constituents Linear:highest E - overcome  4 bending energy loss Complementary to other (pp) collider(s) Other ways to achieve this: – Muon collider 22 May 2012Nikhef strategy: LC (SdJ)2

3. Physics case Standard Model: – Precision EW symmetry breaking physics Higgs properties W/Z properties – Precision top physics – Precision QCD Beyond Standard Model – Direct searches / New particle properties – Indirect searches: quantum loop physics 22 May 2012Nikhef strategy: LC (SdJ)3

4. Physics case: Standard Model - Higgs m H =125 GeV assumed This precision tests loops ! Comparison to LHC ? 22 May 2012Nikhef strategy: LC (SdJ)4 Channel \ √s250-500 GeV3000 GeV H->bb1.1%1% H->cc3.2%1.5% H->gg7% H->  8% H->  3% H->tt10% H->WW1.2%? H->HH<50%<20%

5. Physics case: SM – LHC comparison ? 22 May 2012Nikhef strategy: LC (SdJ)5

6. Physics case: Standard Model – W/Z The ultimate SM test: longitudinal W/Z part of same Higgs doublet as H boson Surprisingly understudied 22 May 2012Nikhef strategy: LC (SdJ)6

7. Physics case: Standard Model – top Threshold scan complementary 22 May 2012Nikhef strategy: LC (SdJ)7

8. Physics case: Beyond Standard Model WIMP from recoil KK graviton productions Contact interactions 22 May 2012Nikhef strategy: LC (SdJ)8

9. Technology case: accelerator Superconducting cavities, 31.5 (-35) MV/m – C-band (5.7GHz) -> S-band (3GHz) -> L-band (1.3GHz) Warm cavities, 100 MV/m – CLIC Plasma wakefield, GV/m-TV/m (W. P. Leemans, et al., GeV electron beams from a centimetre-scale accelerator, Nature Physics 2 (2006) 696) 22 May 2012Nikhef strategy: LC (SdJ)9 9 of 10 produced

10. Technology case: detector(s) Somewhat Accelerator dependent: bunch structure High precision on every individual visible particle Presently two Letters of Intent: – Silicon Detector (SiD) – International Large Detector (ILD) 22 May 2012Nikhef strategy: LC (SdJ)10

11. Funding and politics Significant investment (many, many years of CERN budget) 22 May 2012Nikhef strategy: LC (SdJ)11

12. Funding and politics Site: Japan, CERN, USA, Germany 22 May 2012Nikhef strategy: LC (SdJ)12

13. A plausible strategy Science in steps: 250 GeVH decays 350 GeVt & H 500 GeVHHH couplings 1000 GeVprecision HHH 3000 GeVBeyond SM ? Current window of opportunity: 1.Japan 2.Higgs 22 May 2012Nikhef strategy: LC (SdJ)13 New particles