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Gruppo 1, 25/3/2002

Physics at CERN after the LHC. Gruppo 1, 25/3/2002. Fabiola Gianotti (CERN). The coming years : news from last week … Options for future machines LHC upgrade and CLIC: machines, experiments, physics potentials Muon Collider and  storage ring (low priority … )

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Gruppo 1, 25/3/2002

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  1. Physics at CERN after the LHC Gruppo 1, 25/3/2002 Fabiola Gianotti (CERN) • The coming years : news from last week … • Options for future machines • LHC upgrade and CLIC: machines, experiments, physics potentials • Muon Collider and  storage ring (low priority … ) • Post-LHC physics scenarii • Conclusions Fabiola Gianotti, Gruppo 1, 25/3/2002

  2. Item CERN money saving (MCHF) Industrial services, contracts 170 Fellows and associates 41 Research program (SPS cuts, OPERA) 30 Accelerator R&D 13 Austerity measures 75 LHC computing 60 Energy (cryogenics, SPS cuts) 60 Total 449 Outline of Savings Plan 2002-2009 SPS and PS running : --running time reduced by 30% in 2003, 2006 -- SPS shut-down in 2005 R& D for future accelerators: -- CLIC (CTF3) : budget is ~ 4.5 MCHF per year -- others (e.g.  factory) : ~ no financial support Minimal / narrow program for lab like CERN, only justified by critical situation (e.g. accelerator R&D is few % of total budget at SLAC, DESY, FNAL) Fabiola Gianotti, Gruppo 1, 25/3/2002

  3. NEW LHC SCHEDULE Last dipole : July 2006 Machine closed and cooled down : October 2006 First beams : April 2007 Physics : July 2007 CNGS : - starts in 2006 - has to stay within budget - review ongoing Fabiola Gianotti, Gruppo 1, 25/3/2002

  4. Which machine after the LHC ? Motivation : physics beyond the Standard Model Indeed :LHC will not answer all questions. E.g. can discover SUSY but full understanding of new theory most likely requires measurements at a complementary machine However : -- physics scenario beyond SM not known …. although LEP EW data (light Higgs) favour weak EWSB like in SUSY and disfavour composite Higgs of strongly-interacting models -- unlike for TeV-scale, no compelling motivation today for >> TeV-scales Difficult to take decision today but some answers / clues from LHC data Need vigorous accelerator and detector R & D to be able to take decision by  2010 Fabiola Gianotti, Gruppo 1, 25/3/2002

  5. LHC upgrade : luminosity (L = 1035 cm-2 s-1 ), maybe energy (s = 28 TeV ? ) •  TeV-range e+e- LC (TESLA, NLC, JLC) : s = 0.5 –1.5 TeV, L = 1034 cm-2 s-1 •  multi-TeV e+e- LC (CLIC) : s = 3-5 TeV, L = 1035cm-2 s-1 •  Muon Collider : s  4 TeV, L ~ 1034 – 1035 cm-2 s-1 ? • Three steps :  factory, Higgs factory, high-E muon collider •  VLHC : s = 100-200 TeV, L = 1034 -1035 cm-2 s-1 time scale  2020 time scale > 2020 ring ~ 230 Km Possible options for future machines  and  are most likely not CERN options  has low priority given present “crisis”  Here : ~ only  and  are discussed Fabiola Gianotti, Gruppo 1, 25/3/2002

  6. LHC upgrade • Discussions started in Spring 2000 : • -- luminosity upgrade to L = 1035 • -- s = 28 TeV ? more difficult/expensive than L upgrade • 2 WG set up by CERN DG in Spring 2001 : • -- physics and detectors(convened by M.Mangano, J.Virdee, F.G.) •  final report ~ ready : “ Physics potential and experimental challenges • of the LHC luminosity upgrade ” • -- machine (convened by F.Ruggiero) •  final report in preparation : “ LHC luminosity and energy upgrades : • a feasibility study ” • Motivations : • -- maximum exploitation of existing tunnel, machine, detectors … • -- LHC may give hints for New Physics at limit of sensitivity • -- improve / consolidate LHC discovery potential and measurements Fabiola Gianotti, Gruppo 1, 25/3/2002

  7. From preliminary feasibility studies : • L upgrade to 1035: • -- increase bunch intensity to beam–beam limit  L ~ 2.5 x 1034 • -- halve bunch spacing to 12.5 ns (new RF) • -- change inner quadrupole triplets at IP1 , IP5 •  halve * to 0.25 m • Other options : upgrade injectors to get more brilliant beams, • single 300 m long super-bunch, etc. moderate hardware changes time scale  2012 ? • s upgrade to 28 TeV : • -- ultimate LHC dipole field : B= 9 T  s = 15 TeV •  any energy upgrade requires new machine • -- present magnet technology up to B ~ 10.5 T • small prototype at LBL with B= 14.5 T • -- magnets with B~16 T may be reasonable target for operation • in ~ 2015 provided intense R& D on e.g. high-temperature • superconductors (e.g. Nb3Sn) major hardware changes time scale  2015 ? Fabiola Gianotti, Gruppo 1, 25/3/2002

  8. L = 1035 upgrade “SLHC = Super-LHC” vs s = 28 TeV upgrade Easier for machine Challenging and expensive for machine Major changes to detectors for Modest changes to detectors full benefit, very difficult environment Smaller physics potential: Larger physics potential: -- mass reach 20-30% higher than LHC -- mass reach ~1.5 higher than LHC -- precision measurements possible but -- many improved measurements (e.g. Higgs) -- with significant detector upgrades -- higher statistics than LHC -- challenging due to environment -- LHC-like environment If both : s = 28 TeV + L =1035 : LHC mass reach extended by ~ 2 Here : mainly potential of L upgrade (but comparison with s = 28 TeV available in some cases) Assumptions : -- L dt = 1000 fb-1 per experiment per year of running -- similar ATLAS and CMS performance as at LHC  somewhat optimistic (but performance deterioration not dramatic) Fabiola Gianotti, Gruppo 1, 25/3/2002

  9. If bunch crossing 12.5 ns LVL1 trigger (BCID) • tracker (occupancy) must work at 80 MHz CMS tracker CMS calorimeters  ECAL dose HCAL dose (kGy) (kGy) 0-1.5 3/180.2/1 2.0 20/120 4/25 2.9 200/1200 40/250 3.5 100/600 5 1000/6000 • R (cm) hadron fluence Dose (kGy) • 1014 cm-2 • 30/190 840/5000 • 5/28 190/1130 • 1.5/10 70/420 • 0.3/2 7/40 • 115 0.2/1 2/11 L = 1035 : experimental challenges and detector upgrades • ~ 120 minimum-bias per crossing (compared to ~ 25 at LHC) • occupancy in tracker ~ 10 times larger than at LHC (for same granularity and response time) • pile-up noise in calorimeters ~ 3 times larger (for same response time) • radiation : —— 500 fb-1 = ~ 10 years at LHC —— 3000 fb-1 = ~ 3 years at SLHC 1 Gy = 1 Joule/Kg Fabiola Gianotti, Gruppo 1, 25/3/2002

  10. Trackers : need to be replaced(radiation, occupancy, response time) • -- R > 60 cm : development of present Si strip technology ~ ok • -- 20 < R < 60 cm : development of present Pixel technology ~ ok • -- R < 20 cm : fundamental R & D required (materials, concept, etc.) • -- channel number ~ 5 larger (occupancy)  R&D needed for low cost • Calorimeters : mostly ok • -- ATLAS : space-charge problems in LAr fwd calorimeter • -- CMS : -- radiation resistance of end-cap crystals and electronics ? • -- change scintillator or technique in hadronic end-cap • -- plastic-clad  quartz-clad quartz fibers in fwd calorimeter • Muon spectrometers : mostly ok • -- increase forward shielding  acceptance reduced to ||< 2 • -- space charge effects, aging ? • -- some trigger chambers (e.g. ATLAS TGC) too slow for 12.5 ns • Electronics and trigger : large part to be replaced • -- new LVL1 trigger electronics for 80 MHz • -- R&D needed for e.g. tracker electronics (fast, rad hard) • -- most calorimeter and muon electronics ~ ok (radiation resistance ?) Fabiola Gianotti, Gruppo 1, 25/3/2002

  11. L (cm-2 s-1) Electron efficiencyJet rejection 1034 81% 10600 2200 1035 78% 6800  1130 (GeV) 1034 1035 30-45 33 3.7 60-100 190 27 100-200 300 113 200-350 90 42 pT Examples of (ATLAS) performance at 1035 Full Geant simulation No optimisation done • EM calorimeter energy resolution: e ET= 30 GeV - deterioration smaller at higher E ( pile-up ~ 1/E) - pessimistic : optimal filtering could help • e/jet separation: ET = 40 GeV deterioration smaller at higher E • b-tagging: Rejection against u- jets for 50% b-tagging efficiency assuming same 2-track resolution at 1035 as at 1034 Fabiola Gianotti, Gruppo 1, 25/3/2002

  12. Compact LInear Colliders = 3  5 TeV, L = 1035 Two-beam acceleration : main beam accelerated by deceleratig high-intensity drive beam • Gradient ~ 150 MV/m, RF = 30 GHz  length < 40 Km • Bunch spacing < 1 ns • Test facilities CTF1 and CTF2 : -- two-beam principle demonstrated • -- 150 MV/m achieved with 3 ns bunch trains • CTF3 (2002-2006) : to demonstrate 150 MV/m with 100 ns bunch trains Spring 2000 : CLIC Physics study group set up (convened by A. De Roeck) Fabiola Gianotti, Gruppo 1, 25/3/2002

  13. “ beamstrahlung” s (TeV) 1 3 5 L in 1% s 56 % 30% 25% L in 5% s 71 % 42% 34% TESLA-like detector under study: Event rates/year 3 TeV 5 TeV 1000 fb-1 103 evts 103 evts e+e- tt 20 7 e+e- bb 11 4 e+e- ZZ 27 11 e+e- W+W- 490 205 e+e- H (120 GeV) 530 690 e+e- H+H-(1 TeV) 1.5 1 e+e- (1 TeV) 1.3 1 3-15 cm Si VDET 15-80 cm Si central/ forward disks 80-230 cm TPC or Si tracker 240-280 cm ECAL 280-400 cm HCAL 400-450 cm Coil (4T) 450-800 cm Fe/muon Challenging experimental environment • High intensity beams  strong beam-beam interactions -- distortion of luminosity spectrum -- backgrounds (e.g. e+e- pairs)  high B-field, trackers at R > 3 cm  fwd mask  < 70 • Pile-up : -- bunch x-ing < 1 ns • -- ~ 4   hadrons Evis > 5 GeV per x-ing Need flavour tagging, calo granularity, etc. But what about E-flow for high-E jets ? Fabiola Gianotti, Gruppo 1, 25/3/2002

  14. Examples of SM measurements : -- Triple Gauge Couplings -- Multi gauge boson production -- Rare top decays Physics potentials of the upgraded LHC and CLIC …. a few examples … Note : all results are preliminary …. Note : most of SM physics program (W-mass, top physics, etc.) will be completed at standard LHC. However : rate-limited processes can benefit from SLHC Fabiola Gianotti, Gruppo 1, 25/3/2002

  15. W W g, Z  , k from W    Z , kZ , g1Z from W Z     =e,  1034  =  1035 Triple Gauge Bosons at LHC and SLHC Probe non-Abelian structure of SU (2) and sensitive to New Physics • -couplings increase as ~ s • constrained by tot, high-pT tails k-couplings : softer energy dependence  constrained mainly by angular distributions Expected precision from LEP2 + Tevatron in 2007 :  % Fabiola Gianotti, Gruppo 1, 25/3/2002

  16. 14 TeV 100 fb-128 TeV 100 fb-1 14 TeV 1000 fb-128 TeV 1000 fb-1 (units are 10-3 ),  = 10 TeV  14 TeV 14 TeV28 TeV 28 TeV 100 fb-11000 fb-1100 fb-1 1000 fb-1 DkZ lg1.40.6 0.8 0.2 lZ2.81.82.3 0.9 Dkg 342027 13 DkZ4034 36 13 g1Z 3.8 2.42.30.7 Z Z 95% C.L. constraints for 1 experiment from fits totot, pT, pTZ SLHC sensitivity to , Z, g1Z at level of SM radiative corrections Angular distributions not used  pessimistic for k-couplings These SLHC results do not require major detector upgrades : only high-pT muons and photons used here (assuming trackers not replaced) Fabiola Gianotti, Gruppo 1, 25/3/2002

  17. e+ W- g, Z e.g. W+ e- SLHC SLHC Comparison with TESLA and CLIC (revised version of a figure by T. Barklow) Anomalous contributions depend on scale of New Physics   no limit to desired precision Fabiola Gianotti, Gruppo 1, 25/3/2002

  18. q q W- Z* q Z W Z W+ q q W Z Z q Process Expected events after cuts 6000 fb-1 WWW 2600 WWZ 1100 ZZW 36 ZZZ 7 WWWW 5 WWWZ 0.8 W   Z    = e, Multiple gauge boson production at SLHC - Probe  quartic anomalous couplings (e.g. 5-ple vertex = 0 in SM) - Rate limited at LHC LHC sensitive to some 4-ple vertices SLHC may be sensitive to 5-ple vertex Not yet studied at CLIC … Fabiola Gianotti, Gruppo 1, 25/3/2002

  19. t c,u , Z, g 99% C.L. sensitivity to FCNC BR (units are 10-5) Channel LHC SLHC (600 fb-1) (6000 fb-1) t  q 0.9 0.25 t  qg 61 19 t  qZ 1.1 0.1 only possible if b-tagging performance at SLHC similar to LHC FCNC top decays at SLHC • Most measurements (e.g. mtop ~ 1.5 GeV) limited by systematics •  ~ no improvement at SLHC • Exception : FCNC decays • Some theories beyond SM (e.g. some SUSY models, 2HDM) predict BR  10-5- 10-6, • which are at the limit of the LHC sensitivity • Expected limits from Tevatron Run II in 2007 : BR < 10-3 CLIC : no sensitivity (~ 20 000 tt pairs/year) Fabiola Gianotti, Gruppo 1, 25/3/2002

  20. Examples from Higgs physics : -- Higgs couplings to fermions and bosons -- Higgs self-couplings -- Rare decay modes -- MSSM Higgs sector -- Strongly-interacting Higgs Note : -- Higgs search/discovery program will be completed at standard LHC -- Higgs physics at SLHC requires new trackers (b-tagging, e measurements, etc.) in most cases Fabiola Gianotti, Gruppo 1, 25/3/2002

  21. gHff  deduce f ~ g2Hff Higgs couplings to fermions and bosons Can be obtained from measured rate in a given production channel: • LC : tot and  (e+e- H+X) from data • LHC : tot and  (pp  H+X) from theory  without theory inputs measure • ratios of rates in various channels (tot and  cancel)  f/f’ Closed symbols: LHC 600 fb-1 Open symbols: SLHC 6000 fb-1 Improvement in precision by up to ~ 2 from LHC to SLHC However : not competitive with TESLA and CLIC precision of  % Fabiola Gianotti, Gruppo 1, 25/3/2002

  22. ~ 3v Higgs potential: S B S/B S/B mH = 170 GeV 350 4200 8% 5.4 mH = 200 GeV 220 3300 7% 3.8 6000 fb-1 Higgs self-couplings at SLHC mH2 = 2  v2  probe HHH vertex via double H production LHC :  (pp  HH) < 40 fb mH > 110 GeV + small BR for clean final states  no sensitivity SLHC : HH  W+ W- W+ W-   jj jj studied (very preliminary) Backgrounds (e.g. tt) rejected with b-jet veto and same-sign leptons If : -- KB2 < KS -- B can be measured with data + MC (control samples) -- B systematics < B statistical uncertainty -- fully functional detector (e.g. b-tagging) -- HH production may be observed at SLHC --  may be measured with stat. error ~ 20% Fabiola Gianotti, Gruppo 1, 25/3/2002

  23. - Higgs self-couplings at CLIC mH=120 GeV, 4b final states 5000 fb-1 TESLA :  25% precision 1000 fb-1 CLIC :  7 % precision 5000 fb-1 Fabiola Gianotti, Gruppo 1, 25/3/2002

  24. BR (H  ) ~ 10-4 SM Additional coupling measurement: gH to ~ 15% H  Z   H   mH=130 GeV Signal significance S/B : LHC (600 fb-1) ~ 3.5 SLHC (6000 fb-1) ~ 11 Signal significance S/B : LHC (600 fb-1) ~ 3.5 (gg+VBF) SLHC (6000 fb-1) ~ 7 (gg) Higgs rare decays Fabiola Gianotti, Gruppo 1, 25/3/2002

  25. BR (H  ) ~ 10-4 SM Additional coupling measurement: gH to ~ 15% CLIC, 5000 fb-1 H  Z   gH to ~ 5% H   mH=130 GeV Signal significance S/B : LHC (600 fb-1) ~ 3.5 SLHC (6000 fb-1) ~ 11 Signal significance S/B : LHC (600 fb-1) ~ 3.5 (gg+VBF) SLHC (6000 fb-1) ~ 7 (gg) Higgs rare decays Fabiola Gianotti, Gruppo 1, 25/3/2002

  26. 5 contours, decays to SM particles • In the green region only • SM-like h observable, unless • A, H, H  SUSY particles • LHC can miss part of MSSM Higgs sector 600 fb-1 For mA < 600 GeV, TESLAcan demonstrate indirectly (i.e. through precision measurements of h properties) existence of heavy Higgs bosons at 95%C.L. 6000 fb-1 Region where  1 heavy Higgs observable at SLHC  green region reduced by up to 200 GeV + region accessible directly or indirectly to TESLA fully covered mh < 130 GeV mA mH  mH MSSM Higgs sector : h, H, A, H Fabiola Gianotti, Gruppo 1, 25/3/2002

  27. e+ H- g, Z H+ e- H  tb  Wbb  jjbb  8 jets final state 3000 fb-1 m ~ 4% ttbb backgound CLIC : sensitive to m (A, H, H ) up to  1 TeV e.g. H+H- production  full MSSM Higgs spectrum should be observed Fabiola Gianotti, Gruppo 1, 25/3/2002

  28. q q VL VL VL q VL q Fake fwd jet tag probability from pile-up (preliminary ..) ATLAS full simulation Pile-up included  ~ 280 GeV Strong VL VL scattering at LHC, SLHC If no Higgs, expect strong VLVL scattering (resonant or non-resonant) at LHC :   fb Forward jet tag and central jet veto essential tools against background LHC may observe only non-resonant WLWL  WLWL More channels, e.g. WLZL  WLZL ,ZLZL  ZLZL, may be observed at SLHC  more clues to underlying dynamics Need new trackers (e.g. charge measurement) Fabiola Gianotti, Gruppo 1, 25/3/2002

  29. W  jj W, Z mass resolution ~7% (collimated jets) • CLIC : • -- ~ 4000 events/year at production for m = 2 TeV,  = 85 GeV • -- fully hadronic final states accessible • -- small backgrounds • observation of resonant and non-resonant scattering up to ~ 2.5 TeV in several models E.g. expected significance for non-resonant WLWL  WLWL: LHC (300 fb-1) ~ 5  SLHC (3000 fb-1) ~ 13 K-matrix unitarization model CLIC (1000 fb-1) ~ 70  W  jj Strong VL VL scattering at CLIC Observation of strong EWSB not granted at LHC, SLHC: -- only fully leptonic final states accessible  tiny rates -- non-resonant WLWL : same shapes for signal and background -- relies on fwd jet tag and jet veto performance  observation depends on model parameters Measurement of resonance parameters at CLIC under study (beam polarisation is additional tool)  strong dynamic should be explored in detail Fabiola Gianotti, Gruppo 1, 25/3/2002

  30. Examples of Physics beyond the SM : -- SUSY -- Extra-dimensions -- Z ’ -- Compositeness Fabiola Gianotti, Gruppo 1, 25/3/2002

  31. If SUSY connected to hierarchy problem, some sparticles should be observed at LHC • However: no rigorous upper bound may be at limit of sensitivity • e.g. inverted hierarchy models : up to several TeV first two generations • Expected limits from Tevatron Run II in 2007 : 5 contours 5  discovery reach on CMS LHC  2.5 TeV SLHC  3 TeV s = 28 TeV, 1034  4 TeV s = 28 TeV, 1035  4.5 TeV tan=10 SUSY at LHC, SLHC -- No major detector upgrade needed for discovery: inclusive signatures with high pT calorimetric objects -- Fully functional detectors (b-tag, etc.) needed for precision measurements of SUSY parameters based on exclusive chains (some are rate-limited at LHC) Fabiola Gianotti, Gruppo 1, 25/3/2002

  32. EW  RGE  GUT Examples of mSUGRA points compatible with present constraints Blair, Porod, Zerwas M3 = (from LHC) from precise measurements of e.g. gaugino masses at EW scale reconstruct theory at high E M2 m1/2 M1 SUSY at CLIC Sensitive to ~ all sparticles up to m ~ 1.5-2.5 TeV • can complete SUSY spectrum: some • sparticles not observable at LHC (small S/B) • nor at TESLA (if m > 200-400 GeV) • precision measurements (e.g. masses to 0.1%, • field content) constrain theory parameters Fabiola Gianotti, Gruppo 1, 25/3/2002

  33. Extra-dimensions Several models studied : ADD ( Arkani-Hamed, Dimopoulos, Dvali) : direct production or virtual exchange of a continuous tower of gravitons RS ( Randall-Sundrum) : graviton resonances in the TeV region TeV-1 scale extra-dimensions : resonances in the TeV region due to excited states of SM gauge fields Fabiola Gianotti, Gruppo 1, 25/3/2002

  34. SM wall G G Bulk MPl2  MD+2 R at large distance • If MD 1 TeV : •  = 1 R  1013 m  excluded by macroscopic gravity •  = 2 R  0.7mm  limit of small- scale gravity experiments • …. •  = 7 R  1 Fm R Extra-dimensions are compactified over R < mm Arkani-Hamed, Dimopoulos, Dvali If gravity propagates in 4 +  dimensions, a gravity scale MD 1 TeV is possible Fabiola Gianotti, Gruppo 1, 25/3/2002

  35. f G f • Gravitons in Extra-dimensions get quantised mass:  continuous tower of massive gravitons (Kaluza - Klein excitations) Due to the large number of Gkk , the coupling SM particles - Gravitons becomes of EW strength • Only one scale in particle physics : EW scale • Can test geometry of universe and • quantum gravity in the lab Fabiola Gianotti, Gruppo 1, 25/3/2002

  36. Supernova SN1987A cooling by  emission (IBM, Superkamiokande)  bounds on cooling via Gkk emission: MD > 31 (2.7) TeV  = 2 (3) Distorsion of cosmic diffuse  radiation spectrum (COMPTEL) due to Gkk  : MD > 100 (5) TeV  = 2 (3) large uncertainties but  =2 disfavoured Seattle experiment, Nov. 2000 R > 190 mm MD > 1.9 TeV r Fabiola Gianotti, Gruppo 1, 25/3/2002

  37. q q g G 5 reach MD = gravity scale  = number of extra-dimensions 1st example : direct G production in ADD models at LHC/SLHC  topology is jet(s) + missing ET Expected limits (Tevatron, HERA) in 2007: MD > 2-3 TeV for =3 SLHC : -- no major detector upgrade needed (high-pT calorimetric objects) -- similar reach for virtual G exchange -- G and /Z resonances observable up to 5-8 TeV Fabiola Gianotti, Gruppo 1, 25/3/2002

  38. e- G e+ MD (TeV) 5 TeV 3 TeV 2nd example : virtual G exchange in ADD models at CLIC expect deviations from SM expectation (e.g. cross-section, asymmetries) precise measurements at high-E machines are very constraining Indirect sensitivity up to ~ 80 TeV (depending on model) through precision measurements Fabiola Gianotti, Gruppo 1, 25/3/2002

  39. e+e- + - 3nd example : Graviton resonance production in RS models at CLIC CLIC is resonance factory up to kinematic limit. Precise determination of mass, width, cross-section (from resonance scan `a la LEP1), branching ratios, spin … Fabiola Gianotti, Gruppo 1, 25/3/2002

  40. LHC, SLHC direct discovery reach up to ~ 7 TeV 6 6 Additional gauge bosons : Z ’ For Z-like Z’ with  (Z’) / m(Z’) ~ 3% Mass can be measured to  % (dominant error: calorimeter E-scale up to ~5 TeV, then statistics) • direct discovery reach up to 3-5 TeV: • mass and width can be measured to 10-3 – 10-4 • from resonance scan • indirect reach from precise (~ %) EW measurements • up to ~ 40 TeV CLIC Fabiola Gianotti, Gruppo 1, 25/3/2002

  41. 14 TeV 3000 fb-1 14 TeV 14 TeV 28 TeV 28 TeV 300 fb-1 3000 fb-1 300 fb-1 3000 fb-1 40 60 60 85 Contact interactions at LHC, SLHC Quark sub-structure modifies di-jet angular distribution at Hadron Colliders 95% C.L. lower limits on  (TeV) If b-tagging available can measure jet flavour Fabiola Gianotti, Gruppo 1, 25/3/2002

  42. 1000 fb-1 V ( ) = 2 | |2 + | | 4 mH 2 =2  (mZ) v 2 Not allowed, couplings diverge (  > 1) ~ 115 Not allowed (EW vacuum unstable,  <0) Contact interactions at CLIC • From EW measurements • Sensitive to eeqq, ee   complementary to Hadron colliders CLIC s = 5 TeV can probe  up to ~ 800 TeV Fabiola Gianotti, Gruppo 1, 25/3/2002

  43. SLHC : • -- although some signatures (jets, ETmiss , , etc.) do not require • major detector upgrades, new trackers (b-tag, e, ) allow • larger discovery reach, more convincing results if at limit of • sensitivity, precision measurements  full benefit from L increase • -- improves / consolidates LHC discovery potential and measurements  good physics return for “modest” cost ? • CLIC : • -- direct discovery potential and precise measurements up to • 3-5 TeV can fill LHC “ holes ” in spectrum of New Physics • -- indirect sensitivity up to scales   100-1000 TeV • -- complementary to LHC, SLHC, VLHC • almost “ no-lose theorem” ? SUMMARY • LHC upgrades : • s = 14 TeV, L=1035 (SLHC) : extend LHC mass reach by  30%   7 TeV • s = 28 TeV, L=1034 : extend LHC mass reach by  50%   8 TeV • s = 28 TeV, L=1035 : extend LHC mass reach by  2   11 TeV • s = 28 TeV : • -- significant improvement of LHC discovery potential • -- precision measurements for L = 1034 • however: benefit/cost ratio too small ? Fabiola Gianotti, Gruppo 1, 25/3/2002

  44. Units are TeV (except TGC and WLWL reach) Ldt correspond to 1 year of running at nominal luminosity for 1 experiment PROCESS LHC LC SLHC CLIC CLIC VLHC 14 TeV 0.8 TeV 14 TeV 3 TeV 5 TeV 200 TeV 100 fb-1 500 fb-1 1000 fb-1 1000 fb-1 1000 fb-1 100 fb-1 Squarks 2.5 0.4 31.5 2.5 15 Sleptons 0.34 0.4 1.5 2.5 Z’ 5 8†6 20† 30† 30 q* 6.5 0.8 7.5 3 5 70 * 3.4 0.8 3 5 Extra-dim (=2) 9 5-8.5† 12 20-33† 30-55† 65 WLWL 3.0 7.5 70 90 30 TGC  (95%) 0.0014 0.0004 0.0006 0.00013 0.00008 0.0003  compositeness 35 100 50 300400 130 † indirect reach (from precision measurements) probes directly the 10-100 TeV scale probes indirectly up to 1000 TeV Comparison with TeV LC and VLHC Fabiola Gianotti, Gruppo 1, 25/3/2002

  45.  Factory and Muon Collider : a 3-step project excellent physics potential at each step ! •  factory : • -- Superconducting Proton Linac (SPL) : high-intensity p source (1016 p/s, 2.2 GeV) • using LEP RF cavities. Useful also for LHC, ISOLDE, CNGS (Conceptual Design Rep. ready) • --  collection, cooling, acceleration to ~ 50 GeV, decay   storage ring • -- high-intensity and well-understood (flux, spectrum) e and  beams for • oscillation/mixing matrix studies • Higgs factory : + -  H • -- s  115  1000 GeV • -- better potential than e+e- LC of same s : smaller E-beam spread (~10-5), • better E-beam calibration (to ~10-7 from e spectrum from polarised  decays), •  (+-  H) ~ 40000  (e+e-  H) • e.g. mW7 MeV, mtop MeV, H lineshape (mH  0.1 MeV, H  0.5 MeV at 115 GeV) • High-E Muon Collider : • -- s  4 TeV (-radiation ~ E) • -- better potential than e+e- LC of same s (see above), but no ,  options • -- smaller E-beam spread but  radiation  detector background longer time-scale than CLIC Fundamental questions to be solved for  and  : • cooling (fast ionisation cooling ?) and acceleration (re-circulating LINAC) Fabiola Gianotti, Gruppo 1, 25/3/2002

  46. LHC finds SUSY (Higgs, squarks, gluino, and some gauginos and sleptons)  TeV/multi-TeV LC to complete spectrum ? LHC finds SUSY (Higgs, gluino, stop, some gauginos) but no squarks of first generations  VLHC and multi-TeV LC could be equally useful and complementary ? LHC finds only one SM-like Higgs and nothing else  multi-TeV LC to study Higgs properties and get clues of next E-scale up to 106 GeV ?  give SUSY a last chance with a VLHC ? LHC finds contact interactions   < 60 TeV • VLHC to probe directly scale  ? LHC finds Extra-dimensions  MD < 15 TeV • VLHC to probe directly scale MD ? • LHC finds nothing Higgs strongly interacting or invisible ? •  multi-TeV LC to look for Higgs and get hints of next E-scale ? LHC finds less conventional scenarii or totally unexpected physics  ? Examples of possible post-LHC scenarii and options (speculative …) Note : here LC  Lepton Collider Fabiola Gianotti, Gruppo 1, 25/3/2002

  47. CONCLUSIONS • Good reasons to believe that LHC, although powerful, will not be able • to answer fully to important physics questions and that a new high energy/luminosity • machine will be needed. Similar arguments apply to a 1 TeV LC. • Because we ignore what happens at the TeV scale, and in the absence of theoretical • preference for a specific energy scale beyond the TeV region, difficult to make • a choice before LHC data will become available. • However, to be in a position to make a proposal before/around 2010, • i.e. for completion of the new machine by early 2020, vigorous accelerator and • detector R&D is needed NOW. • Several options considered at CERN: • -- LHC luminosity upgrade (as a natural exploitation/evolution of existing machine). • s = 28 GeV is likely not a large enough step for the cost of a new machine • -- CLIC • -- Muon Collider and neutrino storage ring • Because of CERN financial problems, R&D effort now focused on CLIC: • -- two-beam accelerator principle needs to be demonstrated as soon as possible • -- CLIC has excellent and “almost granted” physics potential • -- could be built on a reasonable time scale Fabiola Gianotti, Gruppo 1, 25/3/2002

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