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Linear e+e- Colliders: Physics and Projects

Linear e+e- Colliders: Physics and Projects. Contents  Recent LC history  The ILC: a TeV collider  CLIC: a multi-TeV collider. De Roeck CERN China-CERN Workshop on Coorperation in High Energy Physics. Linear e+e- Colliders.

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Linear e+e- Colliders: Physics and Projects

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  1. Linear e+e- Colliders: Physics and Projects Contents  Recent LC history  The ILC: a TeV collider  CLIC: a multi-TeV collider De Roeck CERN China-CERN Workshop on Coorperation in High Energy Physics Albert De Roeck (CERN)

  2. Linear e+e- Colliders Since end of 2001 there seems to be a worldwide consensus (ECFA/HEPAP/Snowmass 2001…) The machine which will complement and extend the LHC best, and is closest to be realized, is a Linear e+e- Collider with a collision energy of at least 500 GeV PROJECTS:  TeV Colliders (cms energy up to 1 TeV)  Technology ~ready August’04 ITRP: NLC/GLC/TESLA ILC superconducting cavities  Multi-TeV Collider (cms energies in multi-TeV range)  advanced R&D CLIC (CERN + collaborators)  Two Beam Acceleration Albert De Roeck (CERN)

  3. The Physics case for TeV-LC A collider with energy up to 1 TeV, such as the ILC 1 - Electroweak Symmetry Breaking decipher mechanism for EWSB regardless of what it may be e.g. Higgs precision physics (mass, couplings, self-coupling) 2 - Hierarchy Problem (instability of SM against different scales) direct observations and virtual effects 3 – Dark Matter precision on supersymmetry DM matching future astrophysical experiments 4 – Precision Measurements mass of top-quark, W mass and couplings, weak mixing angle Results of studies from Europe, the Americas, Asia Albert De Roeck (CERN)

  4. A LC is a Precision Instrument • Clean e+e- (polarized intial state, controllable s for hard scattering) • Detailed study of the properties of Higgs particles mass to 0.03%, couplings to 1-3%, spin & CP structure, total width (6%) factor 2-5 better than LHC/measure couplings in model indep. way • Precision measurements of SUSY particles properties, i.e. slepton masses to better than 1%, if within reach • Precision measurements a la LEP (TGC’s, Top and W mass) • Large indirect sensitivity to new phenomena (eg WLWL scattering) A LC will play important role to disentangle the underlying new theory Albert De Roeck (CERN)

  5. LC Physics Examples Understanding SUSY High accuracy of sparticle mass measurements relevant for reconstruction of SUSY breaking mechanism Dark Matter LC will accurately measure m and couplings, i.e. Higgsino/Wino/Bino content  Essential input to cosmology & searches LC will make a prediction of DMh²~ 3% (SPS1a) A mismatch with WMAP/Planck would reveal extra sources of DM (Axions, heavy objects)  Quantum level consistency: MH(direct)= MH(indirect)? sin2W~10-5 (GigaZ), MW ~ 6 MeV (+theory progress)  MH (indirect) ~ 5% 1/M GeV-1 Gaugino mass parameters G. Blair et al Albert De Roeck (CERN)

  6. Generic Linear Collider  J.P. Delahaye 30-40 km All collider elements are challenging • Lot of communalities • between different • LC designs • Common work to which the CERN-CLIC contributes Hence, CERN is involved in LCs on a more general level Albert De Roeck (CERN)

  7. LC Competing technologies (spring 2004) For the main e+e- linac Superconducting cavities Warm cavities Two beam acceleration Albert De Roeck (CERN)

  8. Meanwhile: LC getting on the Roadmap Study groups of ACFA, ECFA, HEPAP The next large accelerator-based project of particle physics should be a linear collider US DOE Office of Science Future Facilities Plan:LC is first priority mid-term new facility for all US Office of Science Major Funding Agencies Regular meetings concerning LC ICFA (February 2004) reaffirms its conviction that the highest priority for a new machine for particle physics is a linear electron-positron collider with an initial energy of 500 GeV, extendible up to about 1 TeV, with asignificant period of concurrent running with the LHC LCWS04 Paris(April 2004) publication of the document “understanding matter, space and time” by 2600 physicists, in support of a linear collider EUROTEV selected by EC 9 MEuro for R&D for a LC Very sizable community wants a e+e- Linear Collider Albert De Roeck (CERN)

  9. Machine Parameters Table from ILC-Technical Review Comittee (2003) http://www.slac.stanford.edu/xorg//ilc-trc/ilc-trchome.html beam size emmitance luminosity Albert De Roeck (CERN)

  10. ITRP Recommendation to ICFA/ILCSC ITRP Mission: select a technology for a machine up to 1 TeV • Conclusion at ICHEP Beijing August ‘04 • Both technologies mature • Select the cold technology to continue Note: technology selected, not a design • Endorsed by ICFA/ILCSC • call project the International Linear Collider ILC Roadmap Start Global Design Initiative/Effort (GDI/GDE): B. Barish Central team director  2006 Conceptual Design Report for Linear Collider >2007 Technical Design Report for a Linear Collider 2009/2010 Aim to be ready for construction. LHC results? Budget? First collisions earliest 2015 ILCSC = International Linear Collider Steering Committee Albert De Roeck (CERN)

  11. CLIC Compact LInear Collider CERN + Albert De Roeck (CERN)

  12. CLIC • An e+e- linear collider optimized for a cms energy of 3 TeV with a luminosity of  1035 cm-2s-1 • Aim: 3 TeV complementing LHC/TeV class LC and breaking new ground, with a final stage up to 5 TeV • To achieve this with reasonable cost (less than ~35 km) and not to many active elements  High accelerating gradient: ~ 150 MV/m Two Beam Acceleration (TBA)  High beamstrahlungs regime to reach high luminosity Challenging beam parameters and machine requirements (nm stability, strong final focus, 30GHz accelerating structures)  CLIC TBA to date the only known way to reach multi-TeV • Test facilities CTF2 (’96-’02): 150-193 MV/m in TBA (16 ns pulses) CTF3 (’02-’09): Test of drive beam, R1’s/ R2’s of TRC (2003) Comparison with ILC TESLA 500 GeV 25MV/m 800 GeV 35MV/m  Future ILC study?: 44MV/m See J.P. Delahaye Albert De Roeck (CERN)

  13. CLIC: a Multi-TeV Linear Collider Physics case for CLIC documented in CERN yellow report CERN-2004-005 (June) and hep-ph/0412251 • CERN: accelerate CLIC R&D support to evaluate the technology by 2009 with extra external contributions  CLIC collaboration. • FAQs: • CLIC technology R&D O(5) years behind ILC R&D • CLIC can operate from 90 GeV 3 (5) TeV . Albert De Roeck (CERN)

  14. CLIC Parameters & Backgrounds CLIC 3 TeV e+e- collider with a luminosity ~ 1035cm-2s-1 (1 ab-1/year) CLIC operates in a regime of high beamstrahlung CLIC parameters old new Time between 2 bunches = 0.67ns • Expect large backgrounds • # of photons/beam particle •  e+e- pair production    events  Muon backgrounds • Neutrons • Synchrotron radiation Expect distorted lumi spectrum Albert De Roeck (CERN)

  15. Resonance Production Resonance scans, e.g. a Z’ 1 ab-1M/M ~ 10-4 & / = 3.10-3 Degenerate resonances e.g. D-BESS model Can measure M down to 13 GeV Smeared lumi spectrum allows still for precision measurements Albert De Roeck (CERN)

  16. Higgs Production • Cross section at 3 TeV: • Large cross section at low masses • Large CLIC luminosity • Large events statistics • Keep large statistics also for highest Higgs masses Low mass Higgs: 400 000 Higgses/year 45K/100K for 0.5/1 TeV LC Albert De Roeck (CERN)

  17. Rare Higgs Decays: H Not easy to access at a 500 GeV collider Also Hbb for masses up to 220 GeV gH Albert De Roeck (CERN)

  18. Higgs Potential: e+e- HH • Precision on HHH for • 5 ab-1 for Higgs masses • in the range • mH = 120 GeV • mH = 140 GeV • mH = 180 GeV • mH = 240 GeV 3 TeV Can improve further by using spin information and polarization (factor 1.7)? precision ~ 6-8% Albert De Roeck (CERN)

  19. Heavy Higgs (MSSM) LHC: Plot for 5  discovery 3 TeV CLIC  H, A detectable up to ~ 1.2 TeV Albert De Roeck (CERN)

  20. Supersymmetry (Battaglia at al hep-ph/0306219) # sparticles that can be detected Higher mass precision at LC vs LHC Mass measurements to O(1%) for smuons Albert De Roeck (CERN)

  21. Precision Measurements Taking into account backgrounds, lumi spectrum, detector… E.g.: Contact interactions: Sensitivity to scales up to 100-800 TeV Albert De Roeck (CERN)

  22. Precision Measurements A light Higgs implies that the Standard Model cannot be stable up to the GUT or Planck scale (1019 GeV) The effective potential blows up, due to heavy top quark mass Allowed corridor but needs strong fine-tuning… The electroweak vacuum is unstable to corrections from scales  >> v= 246 GeV Hambye Riesselmann  New physics must show up before 100-1000 TeV Albert De Roeck (CERN)

  23. Summary: Physics at CLIC Experimental conditions at CLIC are more challenging than at LEP, or ILC Physics studies for CLIC have included the effects of the detector, and backgrounds e.g e+e- pairs and  events. Benchmark studies show that CLIC will allow for precision measurements in the TeV range CLIC has a very large physics potential, reach beyond that of the LHC. Albert De Roeck (CERN)

  24. Detector To exploit the full physics potential excellent detectors will be needed International R&D for ILC for key detector components vertex tracking calorimeter Detector R&D effort will be needed for CLIC as well E.g. Bunch spacing at CLIC= 0.67 nsec at ILC ~320nsec Albert De Roeck (CERN)

  25. Tracking Technologies 3D Silicon Amorphous Silicon • Time stamping will be important O(ns) • Macro-pixels? • Radiation however not a big issue ~ 5 1010 neutrons/cm-2/year • Detector R&D will be required!! Albert De Roeck (CERN)

  26. Calorimetry • Importance of good energy resolution (e.g via energy flow) • Interesting developments in TeV-class LC working groups • e.g. compact 3D EM calorimeters, or “digital” hadronic calorimeters • Detailed simulation studies of key processes required • R&D accordingly afterwards Albert De Roeck (CERN)

  27. CLIC Physics Studies • New & more detailed studies on physics processes • Some processes to be completed, new processes, other backgrounds • Little Higgs Models, Split SUSY, Higgsless ED models… • Detector optimization • Study so far uses a somewhat adapted TESLA detector • Initiate/link with detector R&D • If we want to be ready to know how to built a detector for CLIC (tracker, calorimeter, timestamping) • Study other options for CLIC ? I.e. lower energy ‘start up’ options • ep option (p,A options) • Cliche ( factory) • Z factory? • Higgs factory • Compare with TeV class collider (0.5-1 TeV) • Full energy  and e option for CLIC Topics for possible contributions to the CLIC physics study Albert De Roeck (CERN)

  28. Summary • LC physics and accelerator community has a lot of momentum • ILC design starting to take shape • Machine to produce a CDR soon • All regions actively involved in its preparation • ILC Roadmap aims for a decision/start construction around 2009 • First LHC data should be available by then • These data will be the referee and motivator for the most optimum next machine to be built • CLIC multi-TeV study aims at proof of feasibility/CDR by ~2009 • Has to be ready in case LHC indicates a multi-TeV machine is required. • CLIC has an attractive physics program that can cover the range from the Z-pole (90 GeV) up to the multi-TeV range • Opportunities to join the CLIC physics (& Detector) studies Albert De Roeck (CERN)

  29. Backup Slides Albert De Roeck (CERN)

  30. Multi-TeV collider • Machine Detector Interface related issues to keep in mind if one plans for a facility that can be upgraded to a multi-TeV collider in future • Crossing angle needed of ~20 mrad (multi-bunch kink stability) • Present design: Long collimator syst. and final focus (2.5 km each side) • Energy collimators most important. Fast kicker solution not applicable. Maybe rotating collimators … • Gentle bending to reduce SR & beam spot growth construct the linacs already under an angle of ~ 20 mrad • Internal geometry differences of the collimation system and final focus, allow for enough space in the tunnels (O(m)) Albert De Roeck (CERN)

  31. ITRP Recommendation to ICFA/ILCSC ITRP Mission: select a technology R&D to support both technologies becomes too demanding on resources • Conclusion at ICHEP Beijing August ‘04 • Both technologies mature • Select the cold technology to continue Some arguments in favor of cold Note: technology selected, not a design Endorsed by ICFA/ILCSC  call project the International Linear Collider ILC ILCSC = International Linear Collider Steering Committee Albert De Roeck (CERN)

  32. ILC Parameters & options • Baseline Linear Collider • Minimum energy of 500 GeV, with int. luminosity of 500 fb-1 in the first 4 years • Scan energies between from LEP2 till new energy range: 200-500 GeV with a luminosity ~ s. Switch over should be quick (max 10% of data taking time) • Beam energy stability and precision should 0.1% or better. • Electron beam polarization with at least 80% • Two interaction regions should be planned for • Should allow for calibration running at the Z (s = 90 GeV) • Upgrade: Energy upgrade up to ~ 1 TeV with high luminosity should be planned • Options beyond the baseline: enhance the physics reach • Running as an e-e- collider • Running as a e or  collider • Polarization of the positron beam • Running at Z0 with a luminosity of several 1033cm-2s-1 (GigaZ) • Running at WW mass threshold with a luminosity of a few times 1033cm-2s- Several years of intense physics studies have led to: Albert De Roeck (CERN)

  33. LC Time Scales R. Heuer LCWS04 • ILCSC Road Map • Technology recommendation(done) • Start Global Design Initiative/Effort (GDI/GDE): central team director job as been offered a few days ago • Conceptual Design Report for Linear Collider • Start Global Design Organization (GDI/GDO) • 2007 Technical Design Report for a Linear Collider • 2008 Site selection • 2009/2010 Construction could start (if budget approved) First collisions > 2015? Albert De Roeck (CERN)

  34. Higgs: Strength of a multi-TeV collider • Precision measurements of the quantum numbers and properties of Higgs particles, for large Higgs mass range • Study of Heavy Higgses (e.g. MSSM H,A,H) • Rare Higgs decays, even for light Higgs • Higgs self coupling over a wide range of Higgs masses • Study of the CP properties of the Higgs… Albert De Roeck (CERN)

  35. Higgs Potential Reconstruct shape of the Higgs potential to complete the study of the Higgs profile and to obtain a direct proof of the EW symmetry breaking mechanism  Measure the triple (quartic) couplings process Albert De Roeck (CERN)

  36. Higgs Production • Cross section at 3 TeV: • Large cross section at low masses • Large CLIC luminosity • Large events statistics • Keep large statistics also for highest Higgs masses Low mass Higgs: 400 000 Higgses/year 45K/100K for 0.5/1 TeV LC Albert De Roeck (CERN)

  37. Higgs: Strength of a multi-TeV collider • Precision measurements of the quantum numbers and properties of Higgs particles, for large Higgs mass range • Study of Heavy Higgses (e.g. MSSM H,A,H) • Rare Higgs decays, even for light Higgs • Higgs self coupling over a wide range of Higgs masses • Study of the CP properties of the Higgs… Albert De Roeck (CERN)

  38. Results: e+e- HH • Precision on HHH for • 5 ab-1 for Higgs masses • in the range • mH = 120 GeV • mH = 140 GeV • mH = 180 GeV • mH = 240 GeV 3 TeV Can improve by factor 1.7 if both beams are polarized Albert De Roeck (CERN)

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