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Physics @ CLIC. Albert De Roeck CERN and University of Antwerp and the IPPP Durham. 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
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Physics @ CLIC Albert De Roeck CERN and University of Antwerp and the IPPP Durham
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) R&D CLIC (CERN + collaborators) Two Beam Acceleration
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) LC will very likely play important role to disentangle the underlying new theory
LC: Few More 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)? sin2W~10-5 (GigaZ), MW ~ 6 MeV(?) (+theory progress) MH (indirect) ~ 5% 1/M GeV-1 Gaugino mass parameters G. Blair et al F. Richard/SPS1a
CTF2: CLIC Test Facility 2 Demonstrated that 2 beam acceleration works Reached up to 190 MV/m for short pulses (16ns)
Building CLIC at CERN? It is possible! Geological analyses show that there is a contineous stretch of 40 km parallel to the Jura and the lake, with good geological conditions. Reminder
Experimental Issues: Backgrounds CLIC 3 TeV e+e- collider with a luminosity ~ 1035cm-2s-1 (1 ab-1/year) To reach this high luminosity: CLIC has to operate in a regime of high beamstrahlung • Expect large backgrounds • # of photons/beam particle • e+e- pair production events Muon backgrounds • Neutrons • Synchrotron radiation Expect distorted lumi spectrum Report Old Values
Experimental issues: Luminosity Spectrum Luminosity spectrum not as sharply peaked as e.g. at LEP or TESLA/NLC
e+e- Pair Production Coherent pair production number/BX 4.6 109 energy/BX 3.9 108 TeV Disappear in the beampipe Can backscatter on machine elements Need to protect detector with mask Incoherent pair production: number/BX 4.6 105 energy/BX 3.9 104 TeV Can be suppressed by strong magnetic field in of the detector hits/mm2/bunch train 4T field 30mm O(1) hit/mm2/bunch train
Background hadrons: 4 interactions/bx with WHAD>5 GeV Neutral and charged energy as function of cos per bx Particles accepted within > 120mrad For studies: take 20 bx and overlay events
Muon Background Muon pairs produced in electromagnetic interactions upstream of the IP e.g beam halo scraping on the collimators GEANT3 simulation, taking into account the full CLIC beam delivery system # of muons expected in the detector ~ few thousand/bunch train (150-300 bunches/100-150ns) OK for (silicon like) tracker Calorimeter? ~20 muons per bx 1 shower >100 GeV/5 bx
Studies include background, spectra,… Physics generators (COMPHEP PYTHIA6,… ) + CLIC lumi spectrum (CALYPSO) + hadrons background e.g. overlay 20 bunch crossings (+ e+e- pair background files…) Detector simulation (2004) SIMDET (fast simulation) GEANT3 based program Studies of the benchmark processes include backgrounds, effects of lumi spectrum etc.
Detector:Active (small) group at CERN now: backgrounds, calorimetry, Time stamping, forward region… Weekly meetings…
Example B-tagging • B-Decay length is long! • Define Area of Interest by 0.04 rad cone around the jet axis • Count hit multiplicity (or pulse height) in Vertex Track layers • Tag heavy hadron decay by step in detected multiplicity Can reach 50% eff./~80% purity
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/Join ILC detector efforts
General Physics Context • New physics expected in TeV energy range • Higgs, supersymmetry, extra dimensions, …? • LHC will indicate what physics, and at which energy scale • Two scenarios: • New physics at a low energy scale • But perhaps more particles/phenomena at higher energies (e.g., supersymmetry) • New physics threshold at higher energy scale • In many scenarios, e.g., SUSY, LHC will soon tell us the threshold
Example: Resonance Production Resonance scans, e.g. a Z’ 1 ab-1M/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
Physics Case: A light Higgs Low mass Higgs: 400 000 Higgses/ O(500 K) Higgses/year Allows to study the decay modes with BRs ~ 10-4 such as H and Hbb (>180 GeV) Eg: determine gH to ~4% Large cross sections Large CLIC luminosity Large events statistics Keep large statistics also for highest Higgs masses
Physics case: 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
Physics case: the 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 Can measure the Higgs potential for Higgs even for masses up to 300 GeV with precision up to 5-10% (using polarization/weighting)
Physics case: Heavy Higgs (MSSM) LHC: Plot for 5 discovery 3 TeV CLIC H, A detectable up to ~ 1.2 TeV
Physics case: SUSY measurements LC/LHC complementarity Precision measurements at ILC/CLIC Eg. 1150 GeV smuon mass to O(1%) Will a 0.5-1 TeV collider be enough? Benchmark Scenarios: CMSSM Allowed by present data constraints ADR,F., Gianotti,JE,F. Moortgat, K. Olive, L. Pape hep-ph/0508198
Susy Mass Measurements Momentum resolution (G3) Mass measurements to O(1%) Momentum resolution pt/pt2 ~ 10-4 GeV-1 adequate for this measurement
Physics Case: Extra Dimensions Universal extra dimensions: Measure all (pair produced) new particles and see the higher level excitations RS KK resonances… Scan the different states
Precision Measurements E.g.: Contact interactions: Sensitivity to scales up to 100-400 TeV
Indicative Physics Reach Ellis, Gianotti, ADR hep-ex/0112004+ few updates Units are TeV (except WLWL reach) Ldt correspond to 1 year of running at nominal luminosity for 1 experiment • PROCESS LHCSLHC DLHC VLHCVLHC ILC CLIC • 14 TeV14 TeV 28 TeV 40 TeV 200 TeV 0.8 TeV 5 TeV • 100 fb-11000 fb-1 100 fb-1 100 fb-1100 fb-1 500 fb-1 1000 fb-1 • Squarks 2.534 5200.4 2.5 • WLWL24 4.5 7 18 6 90 • Z’ 56811 358†30† • Extra-dim (=2) 91215 25 655-8.5† 30-55† • q* 6.57.5 9.5 13 750.8 5 • compositeness 3040 40 50100 100 400 TGC () 0.00140.0006 0.0008 0.0003 0.0004 0.00008 † indirect reach (from precision measurements) Approximate mass reach machines: s = 14 TeV, L=1034 (LHC) : up to 6.5 TeV s = 14 TeV, L=1035 (SLHC) : up to 8 TeV s = 28 TeV, L=1034 : up to 10 TeV Extend this table
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. • Ongoing now: Detector studies and R&D • Tracking with good time stamping, - - • improved calorimetry, pflow, mask area,…
Summary: Scenarios with early LHC data… • New physics shows up at the LHC CLIC will • Complete the particle spectra, with a very high reach • Measure accurately parameters of the model (LC quality) • Only a light Higgs at the LHC CLIC will • Measure its properties very accurately, like ILC and more.. • Extend the LHC direct search reach for non-colored particles • Extend the indirect search reach to a scale of 500 (1000?) TeV via precision measurements • No signs of new physics or a Higgs at the LHC CLIC can • Study WW scattering in the 1-2 TeV range in detail • Extend the LHC direct search reach for non-colored particles • Extend the indirect search reach to a scale of 500 (1000?) TeV via precision measurements