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The I nternational L inear C ollider program.

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  1. The International Linear Collider program. Marcello Piccolo LNF-INFN FrontierScience, Milano Sept. 2005

  2. Agenda • Brief historical excursus • The Physics case • The experimental challenges • Detector design (s) • Time scale • Conclusions M.Piccolo, Frontierscience, Milano Sept. 2005

  3. The start of the O(1TeV) L.C. • It is difficult to set a start date for a program that was in the back of at least 50% of particle physicists mind since at least 25 years. • I will arbitrarily set the start date at the Saariselka ( Finland ) meeting in September 1991. • It might be interesting to remember which kind of environment we were living in. M.Piccolo, Frontierscience, Milano Sept. 2005

  4. The lepton collider Physics at the end of 1991 • Going back to the summer of 1991 • 106 Z collected at LEP • The Standard Model was capable of describing everything LEP would turn out. • E.W. fits were almost perfect • The four LEP detectors were just turning toward heavy quark Physics. • For the record E.W. fits were giving : Mtop=120 ± 40 GeV/c2 • CDF had an upper limit on top mass at 91 GeV/c2 M.Piccolo, Frontierscience, Milano Sept. 2005

  5. The men with vision • Maury Tigner • The first one to think of it. • Nuovo Cimento 37 (1965) 1228 • Burt Richter • The first one to do it • SPC SLC • (Late) Bijorn Wiik • The superconducting RF advocate • TESLA ILC • His legacy is embedded the actual program M.Piccolo, Frontierscience, Milano Sept. 2005

  6. The study groups • Originally Europe, Japan and USA organized their own study groups. • After a while it was realized that a common framework was needed, and the LCWS was organized, with the aim of bringing together the regional groups to share experiences, results and …frustrations • This in my opinion was the starting of the global character of the effort. • Now here we are with a programs that carries the word International as a first name. M.Piccolo, Frontierscience, Milano Sept. 2005

  7. The Physics program : seeking answers the TeV Scale The TeV energy region hold the promise of giving back answers to our quests. Origin of mass and electro-weak symmetry breaking Why such a disparity between mweak and mPlanck What is most of the matter in the Universe made of and more… The Tevatron is already at work to open a window into this regime. LHC will allow a (quasi) complete view on phenomena at the TeV scale! M.Piccolo, Frontierscience, Milano Sept. 2005

  8. Will the LHC be enough ? • Although the LHC is the most powerful research instrument ever built in our field, it does have limitations: • LHC detectors record about 10-5 of the total cross section • Analysis will be carried out on 10-10 of the total cross section. • No events balance visible longitudinal momentum. • Events with missing neutrals have unknown pt • High-purity b tagging, any charm tagging and t tagging is difficult • Most LHC analyses rely on a model. • They are powerful if the underlying assumptions are correct, not so powerful if wrong. M.Piccolo, Frontierscience, Milano Sept. 2005

  9. ILC Physics Case (TESLA TDR, Snowmass01, ACFA report, …) • Whatever LHC will find, one CANNOT give up the ILC, that warrants a Physics program which stands on his own feet. • If there is a ‘light’ Higgs (consistent with precision EW) •  proof that it is a particle responsible for giving masses (a) • 2. If there is a ‘heavy’ Higgs (inconsistent with precision EW) •  verify the Higgs mechanism is at work as in (a) •  understand (in)consistencies with S.M. • 3. 1./2. & new states (SUSY, XD, little H, Z’, …) •  A completely spectroscopy is available to be discovered and measured • 4. No Higgs, no new states (inconsistent with precision EW) •  find out what is wrong with the S.M. •  look for threshold effects of strong EWSB M.Piccolo, Frontierscience, Milano Sept. 2005

  10. ILC physics case Produce new particleslook at deviations Look at known processes and find deviations from the expected, through virtual effects. Needs good experimental work AND good knowledge of what to expect. Peek deep intomulti-TeV region Find new type of states and measure it(cross sections, masses, BR’s, Quantum numbers) M.Piccolo, Frontierscience, Milano Sept. 2005

  11. p e+ e- p Hadrons cry to loud (B. Toushek ca. 1960) • Electron positron collisions at high energy allow an almost complete • exploration of the phenomena deemed relevant to EWSB. • The initial state is made of individual constituents, and this provide some advantages with respect to protons. • very well defined (and tunable) centre-of-mass energy • ….and all of it usable. • clean, fully reconstructable events (no unknown pl ) • polarized beams. • moderate backgrounds • Unfortunately chronical lack of counting rate. M.Piccolo, Frontierscience, Milano Sept. 2005

  12. The ILC • ILC baseline parameters currently being discussed • Center-of-Mass Energy ~ 90 – 1000 GeV • Baseline Luminosity :2x1034 cm-2s-1 (>1000xLEP) • Time Structure :5 (10?) Bunch-trains/s • Time between collisions: ~ 300 (150) ns e.g. TESLA TDR • `Backgrounds‘ (depends on ILC parameters) e+e-gqq ~100/hr e+e-gW+W- ~1000/hr e+e-gtt ~50/hr e+e-gHX ~10/hr e+e-gqq ~0.1 /Bunch Train e+e-ggggX ~200 /Bunch Train ~500 hits/BX in Vertex det. ~5 tracks/BX in TPC • Event rates modest – small compared to LHC M.Piccolo, Frontierscience, Milano Sept. 2005

  13. Configuration Parameter Space M.Piccolo, Frontierscience, Milano Sept. 2005

  14. Impact on Detector Design • Radiation hardness not a big concern. • Time structure of the machine not demanding. • Worst type of Physics background gg. • Angle crossing to be studied in detail. • Final focus lenses (L* ) have big effect on backgrounds The detector design dictated by Physics MDI + crossing-angle important : might place constraint on design M.Piccolo, Frontierscience, Milano Sept. 2005

  15. Physics processes • To asses the capabilities of the ILC, I will go over few individual reactions: • Higgs Physics • Super symmetry studies • Gauge bosons • Top M.Piccolo, Frontierscience, Milano Sept. 2005

  16. Higgs Physics • If can use Higgstrahlung,model • independent observation. • mass measurements • absolute branching ratios • total width • spin, CP • top Yukawa coupling • self coupling Garcia-Abia et al M.Piccolo, Frontierscience, Milano Sept. 2005

  17. LHC will discover some Higgs, if it is there within three years (2011?) Will a discovery be enough ? I doubt it. Let us suppose to discover Hgg , and to see, as a cross check a final state ttH. Technipion? Scalar or pseudo-scalar? Does it couple with W/Z? Higgs at LHC M.Piccolo, Frontierscience, Milano Sept. 2005

  18. Legitimate questions • Was the Higgsboson discovered ? • Is it the particle responsible for mass ? • Does it have the correct spin parity assignment 0+? • Is it really the condensate that fills the Universe ? • To prove that it is indeed what gives mass to particles • Spin/Parity • Couplings • Vacuum expectation value • Branching Ratios • Self coupling M.Piccolo, Frontierscience, Milano Sept. 2005

  19. Angular distributions in e+e–ZX depend on X=h, A, V is it a 0+? Higgs Boson at LC M.Piccolo, Frontierscience, Milano Sept. 2005

  20. Branching Fractions prove couplings  mass.  The Higgs is responsible for masses. (Battaglia) Higgs Boson at LC M.Piccolo, Frontierscience, Milano Sept. 2005

  21. Final state ZH ALR is proof that is produced by s-channel Z-exchange If Z gauge boson, H scalar boson  only two vertices possible A VEV is needed to have a ZZH vertex. Measurement of gZ will prove that Z mass is (partly) due to the scalar. Higgs Boson at LC H. Murayama LBL-38891 M.Piccolo, Frontierscience, Milano Sept. 2005

  22. SM 2HDM/MSSM Precision Higgs physics Yamashita et al M.Piccolo, Frontierscience, Milano Sept. 2005 Zivkovic et al

  23. Now, we have the Higgs and we know is the one that generates masses…… • The S.M. assumes a negative m. Why ? • Yes, there is a condensate that shields the weak force. • Why do we have something that condenses ? Why the condensation scale ~TeV<<MPl M.Piccolo, Frontierscience, Milano Sept. 2005

  24. Possible (model) solutions • Super symmetry • Crisis with the electron self energy: ….introduction of antimatter • Double # particles  + boson to fermion and viceversa • Cooper pair mechanism • Cooper pairs: two electrons bond together • Higgs as a fermion antifermion pair  Technicolor • Physics ends @ TeV scale • Ultimate scale: quantum gravity • Gravitational effects @ ~TeV  hidden dimensions M.Piccolo, Frontierscience, Milano Sept. 2005

  25. 200 3000 500 1000 Supersymmetry • If it is there LHC will discover super symmetry; however many hard questions will be still unanswered or partially answered: • is it really SUSY? (measurement of quantum numbers) • how is it realized? (MSSM, NMSSM, …) • how is it broken? • ILC will be able to provide answers to these questions! • Make full use of the flexibilityof the machine: • tunable energy • polarized beams • possibly e-e- and  collisions Sobloher M.Piccolo, Frontierscience, Milano Sept. 2005

  26. To prove : effective super-partners Spins differ by 1/2 Same quantum numbers SU(3)SU(2)U(1) Super symmetric couplings Spin 0? Super symmetry at LC M.Piccolo, Frontierscience, Milano Sept. 2005

  27. Supersymmetry at LC (cont.) Two methods to obtain absolute sparticle masses: in the continuum: at the kinematic threshold: Martyn Freitas • many more observables than just masses: • angular distributions, FB-asymmetries- cross sections- LR-asymmetries- ratios of branching ratios • possibility to determine SUSY parameters without many model assumptions M.Piccolo, Frontierscience, Milano Sept. 2005

  28. Supersymmetry LC + LHC A LHC/LC joint effort: errors of a 19-parameter fit using ILC+LHC: The overall results on SS data fitting: It is clear that neither of the two programs would have such an analyzing Power. Bechtle et al allows for model-independent investigation of GUT/Planck scale features of the theory: Porod et al M.Piccolo, Frontierscience, Milano Sept. 2005

  29. DM/DM main sensitivity bulk 3.5% focus 1.9% co-ann. 6.5% funnel 3.1% The Cosmic Connection SUSY provides excellent candidate for dark matter (LSP) (Other models provide TeV-scale WIMPs too) Sensitivity for DM search at accelerators of the same order as astrophysics searches…. ALCPG study/prel. M.Piccolo, Frontierscience, Milano Sept. 2005

  30. And if no Higgs comes around ? Cross section for weak vector boson scattering violates unitarity at ~1.2 TeV, and no new resonances appear ILC sensitivity deep into multi-TeV region from VB final states eff. Lagrangian parametersof strong EWSB: Higgsless model: new resonancein WZWZ Coupling structure from ILC if resonance seen by LHC M.Piccolo, Frontierscience, Milano Sept. 2005 Birkedal et al. Krstonosic et al.

  31. We know that is there.Threshold scan provides remarkable improvement on mass measurementTheory (NNLL) controls mt(MS) to 100 MeV Top • very precise mtop vital • improved SM fits- MSSM (mh prediction)- DM-density in mSugra- … Hoang et al Heinemeyer et al M.Piccolo, Frontierscience, Milano Sept. 2005

  32. Detector Design for the ILC Optimize the detector so thatevery bit of luminosity counts In e+e- colliders we always fight with small cross sections. Limit systematic errors Requirements differentfrom LHC detectors Overall detector concept R&D on key components M.Piccolo, Frontierscience, Milano Sept. 2005

  33. A detector with Particle flow • To exploit to the fullest the ILCenvironment one seeks complete • reconstruction of complex final states (multi-jets, tau’s) • often accompanied by missing-E • How can we achieve the very best • energy resolution for jets ? • Generally accepted paradigm: • Particle flow • Particle flow is: • a detector concept • and an algorithm M.Piccolo, Frontierscience, Milano Sept. 2005

  34. The Particle Flow Algorithm Basic idea: reconstruct every single particle in the event for each particle type exploit the detector subsystem which can do that best! ~60% charged  tracker ~30% photons (from 0)  ECAL ~10% neut. hadrons  HCAL sounds reasonablechallenge: cluster mixing/double counting Separate charged from neutral: B field, R, trans. granularity, material EM from HAD: trans. + long. granularity (“shower tracking”) Goal : DE/E = 30%/E0.5 M.Piccolo, Frontierscience, Milano Sept. 2005

  35. The Particle Flow Algorithm (cont.) Resolution terms relevant: hadronic energy and wrong clustering Build the best hadronic calorimeter Minimize wrong clustering Granularity M.Piccolo, Frontierscience, Milano Sept. 2005

  36. Detector concept studies • 3 different incarnations of a PF detector studied • They have a lot in common: • both ECAL+HCAL inside coil- highly-granular calorimeter- precision pixel vertex detector- common R&D on components! • concepts, but no closed ‘collaboration’ • They differ in: • choice of tracking: TPC vs. Si • magnetic field 3 – 5 T • inner radius of ECAL • choice of ECAL readout Si vs Sc SiD www-sid.slac.stanford.edu LDC www.ilcldc.org GLD ilcphys.kek.jp/gld/ M.Piccolo, Frontierscience, Milano Sept. 2005

  37. A different detector concept • At the Snowmass meeting in August a new detector concept was presented: • The main difference with respect to the traditional PFA detectors is that the calorimeter system on which is based can, by construction, separate e.m. energy, e.m. + hadronic energy and may be the binding energy of nuclear components ….. M.Piccolo, Frontierscience, Milano Sept. 2005

  38. Dual-Readout Module (DREAM) “Unit cell” M.Piccolo, Frontierscience, Milano Sept. 2005

  39. Design Issues and Detector R&D Detector integral part of ILC Design – meet schedule of GDE Concept optimisation & R&D to be carried out ….since yesterday! Key components: 1. Vertex Detector 2. Charged Particle Tracking 3. Calorimetry 4. Muon system 5. Trigger 6. Forward Region 7. Machine Detector Interface R&D review Panel established by world-wide LC study to promote and coordinate detector R&D for the ILC Keeps tabs of R&D activities around the world at: https://wiki.lepp.cornell.edu/wws/ M.Piccolo, Frontierscience, Milano Sept. 2005

  40. Important for many physics analyses e.g. couplings of a low mass Higgs Want to prove gHff~mf O(%)measurements of the branching ratios Hgbb,cc,gg do heavy flavour tagging is a tool of choice Vertex Detector ( the GLD preliminary optimization) We like to be better than before sd0 ~aÅb/[p(GeV)bsin3/2q] Goal:a=5mm,b=10mm a: point resolution, b : multiple scattering M.Piccolo, Frontierscience, Milano Sept. 2005

  41. T. Maruyama B=5 T Main design considerations: • Inner radius: ~20 mm for impact parameter resolution the smaller the better • Layer Thickness: as thin as possible minimize conversions, reduce M.S. Constraints: • Inner radius constrained by e+e-pair depends onthe f.f. details + B field • Layer thickness depends on Si technology In the end, design driven by machine + technology ! GLD Baseline design: GLD Baseline • Fine pixel CCDs (FPCCDs) • Point resolution : 5 mm • Inner radius : 20 mm • Outer radius : 50 mm • Polar angle coverage : |cosq|<0.9 BUT ultimate design depends on worldwide detector R&D M.Piccolo, Frontierscience, Milano Sept. 2005

  42. Backgrounds in GLD VTX • Assuming to be able to bear 0.5% occupancy, set the radius of the first layer accordingly How much of a disadvantage is B = 3T ? 5 T 3 T 4 T Sugimoto • GLD VTX Forced to a slightly larger inner radius : 2mm ? • Will depend on ILC parameters/MDI ! • This is a disadvantage of lower B-field in GLD concept • How much does the larger inner radius matter ? M.Piccolo, Frontierscience, Milano Sept. 2005

  43. T.Kuhl Rinner = 26mm Rinner = 15mm • Main impact – charm tagging, e.g. Tesla study • Here charm-tagging efficiency for 70 % purity decreases from 45 %  30 % as Rinner increased from 15 mm  26 mm NOTE: not completely fair comparison as different wafer thickness • 3 Tesla field not helpful from point of view of charm-tagging • BUT probably not a big concern M.Piccolo, Frontierscience, Milano Sept. 2005

  44. 750 x 400 pixels 20 m pitch CPR1 CPR1 Vertex Detector Many technologies under study – very active field CCD DEPFET MAPSand many others… Mimosa 9 (MAPS) CCD with column par. r/o DEPFET 1 MPixel M.Piccolo, Frontierscience, Milano Sept. 2005

  45. Central Tracking Driving Physics:Particle Flow: efficiency (kinks , high dE/dx), resolution less importantHiggs recoil mass, SUSY di-lepton endpoints: momentum resolution Two options: Gaseous or Silicon tracker? TPC: >200 3D space pointswith ‘gas type’ point-res O(100µm)(LDC, GLD) Si: 5 (pix) + 5 (strips)high-res pointspoint-res o(few µm)(SiD) M.Piccolo, Frontierscience, Milano Sept. 2005

  46. TPC R&D Use Micro Pattern Gas Detectors (GEMs, MicroMegas) for gas amplification • native 2D structure- ion-feedback suppression built in • - thin end-plates • R&D topics: • stable operation on large scale- optimize resolution/pad geometry- operation in magnetic field- field cage design Significant effort worldwideLC-TPC collaboration M.Piccolo, Frontierscience, Milano Sept. 2005

  47. Central Tracking: Silicon Tracker SiLC collaboration R&D: long ladders (Reduce M.S.)long shaping time: low noise develop r/o chipspattern recognition  use VTX as seed GOAL: testbeam in 2006 momentum resolution: simulation FE prototype ASIC M.Piccolo, Frontierscience, Milano Sept. 2005

  48. Calorimetry Driving physics: Jet energy resolution in multi-jet (6,8,..) events tau reconstruction non-pointing photons E.G. : Strong EW symmetry breaking distinguish W and Z in their hadronic decays w/o kinematic constraints ILC goal ALEPH like resolution M.Piccolo, Frontierscience, Milano Sept. 2005

  49. The H self coupling M.Piccolo, Frontierscience, Milano Sept. 2005

  50. Calorimetry Calorimeter and Particle Flow algorithm are a real challenge Present technologies under study: EM calorimeter: Si W (SiD,LDC), Sc W (GLD) HAD calorimeter: scintillating tiles (‘analog’) RPC, GEM, tiles (‘digital’) addressed by a world-wide R&D effort e.g. CALICE: 26 Institutes, 9 Countriesin 3 Regions ECAL 1st testbeamat DESY 2 electrons, ~3cm apart Testbeam data! M.Piccolo, Frontierscience, Milano Sept. 2005