1. Fabiola Gianotti, Gruppo 1, 25/3/20021 Gruppo 1, 25/3/2002 Fabiola Gianotti (CERN) Physics at CERN after the LHC 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

2. Fabiola Gianotti, Gruppo 1, 25/3/20022 Outline of Savings Plan 2002-2009 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 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)

3. Fabiola Gianotti, Gruppo 1, 25/3/20023 NEW LHC SCHEDULE 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

4. Fabiola Gianotti, Gruppo 1, 25/3/20024 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

5. Fabiola Gianotti, Gruppo 1, 25/3/20025 Possible options for future machines  LHC upgrade : luminosity (L = 10 35 cm -2 s -1 ), maybe energy (  s = 28 TeV ? )  TeV-range e + e - LC (TESLA, NLC, JLC) :  s = 0.5 –1.5 TeV, L = 10 34 cm -2 s -1  multi-TeV e + e - LC (CLIC) :  s = 3-5 TeV, L = 10 35 cm -2 s -1  Muon Collider :  s  4 TeV, L ~ 10 34 – 10 35 cm -2 s -1 ? Three steps : factory, Higgs factory, high-E muon collider  VLHC :  s = 100-200 TeV, L = 10 34 - 10 35 cm -2 s -1 time scale  2020 time scale > 2020 ring ~ 230 Km  and  are most likely not CERN options  has low priority given present “crisis”  Here : ~ only  and  are discussed

6. Fabiola Gianotti, Gruppo 1, 25/3/20026 LHC upgrade Discussions started in Spring 2000 : -- luminosity upgrade to L = 10 35 --  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

7. Fabiola Gianotti, Gruppo 1, 25/3/20027 From preliminary feasibility studies : L upgrade to 10 35 : -- increase bunch intensity to beam–beam limit  L ~ 2.5 x 10 34 -- 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.  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. Nb 3 Sn) moderate hardware changes time scale  2012 ? major hardware changes time scale  2015 ?

8. Fabiola Gianotti, Gruppo 1, 25/3/20028  s = 28 TeV upgrade L = 10 35 upgrade “SLHC = Super-LHC” vs 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 =10 35 : 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)

9. Fabiola Gianotti, Gruppo 1, 25/3/20029 L = 10 35 : experimental challenges and detector upgrades If bunch crossing 12.5 ns  LVL1 trigger (BCID) tracker (occupancy) must work at 80 MHz ~ 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 : R (cm) hadron fluence Dose (kGy) 10 14 cm -2 4 4 30/190 840/5000 11 11 5/28 190/1130 22 22 1.5/10 70/420 75 75 0.3/2 7/40 115 0.2/1 2/11 CMS tracker  ECAL dose HCAL dose (kGy) (kGy) 0-1.5 3/18 0.2/1 2.0 20/120 4/25 2.9 200/1200 40/250 3.5 100/600 5 1000/6000 CMS calorimeters —— 500 fb -1 = ~ 10 years at LHC —— 3000 fb -1 = ~ 3 years at SLHC 1 Gy = 1 Joule/Kg

10. Fabiola Gianotti, Gruppo 1, 25/3/200210 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 ?)

11. Fabiola Gianotti, Gruppo 1, 25/3/200211 EM calorimeter energy resolution: e  E T = 30 GeV - deterioration smaller at higher E (  pile-up ~ 1/E) - pessimistic : optimal filtering could help Examples of (ATLAS) performance at 10 35 e/jet separation: L (cm -2 s -1 ) Electron efficiency Jet rejection 10 34 81% 10600  2200 10 35 78% 6800  1130 E T = 40 GeV b-tagging : (GeV) 10 34 10 35 30-45 33 3.7 60-100 190 27 100-200 300 113 200-350 90 42 pTpT Rejection against u- jets for 50% b-tagging efficiency assuming same 2-track resolution at 10 35 as at 10 34 Full Geant simulation No optimisation done deterioration smaller at higher E

12. Fabiola Gianotti, Gruppo 1, 25/3/200212 Compact LInear Collider  s = 3  5 TeV, L = 10 35 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)

13. Fabiola Gianotti, Gruppo 1, 25/3/200213 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  < 7 0 Pile-up : -- bunch x-ing < 1 ns -- ~ 4   hadrons E vis > 5 GeV per x-ing  s (TeV) 1 3 5 L in 1%  s 56 % 30% 25% L in 5%  s 71 % 42% 34% TESLA-like detector under study: 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 Event rates/year 3 TeV 5 TeV 1000 fb -1 10 3 evts 10 3 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 “ beamstrahlung” Need flavour tagging, calo granularity, etc. But what about E-flow for high-E jets ?

14. Fabiola Gianotti, Gruppo 1, 25/3/200214 Physics potentials of the upgraded LHC and CLIC …. a few examples …  Examples of SM measurements : -- Triple Gauge Couplings -- Multi gauge boson production -- Rare top decays 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

15. Fabiola Gianotti, Gruppo 1, 25/3/200215 Triple Gauge Bosons at LHC and SLHC WW , Z Probe non-Abelian structure of SU (2) and sensitive to New Physics ,  k  from W    Z,  k Z, g 1 Z from W Z  =e,  10 34 =  10 35 -couplings increase as ~ s   constrained by  tot, high-p T tails k-couplings : softer energy dependence  constrained mainly by angular distributions Expected precision from LEP2 + Tevatron in 2007 :  %

16. Fabiola Gianotti, Gruppo 1, 25/3/200216 95% C.L. constraints for 1 experiment 14 TeV 14 TeV 28 TeV 28 TeV 100 fb -1 1000 fb -1  1.4 0.6 0.8 0.2 Z 2.8 1.8 2.3 0.9  k  34 20 27 13  k Z 40 34 36 13 g 1 Z 3.8 2.4 2.3 0.7 (units are 10 -3 ),  = 10 TeV from fits to  tot, p T , p T Z  Z kZkZ Z 14 TeV 100 fb -1 28 TeV 100 fb -1 14 TeV 1000 fb -1 28 TeV 1000 fb -1 SLHC sensitivity to , Z, g 1 Z 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-p T muons and photons used here (assuming trackers not replaced)

17. Fabiola Gianotti, Gruppo 1, 25/3/200217 Comparison with TESLA and CLIC W+W+ W-W- , Z e+e+ e-e- Anomalous contributions depend on scale of New Physics   no limit to desired precision e.g.SLHC SLHC ( (revised version of a figure by T. Barklow)

18. Fabiola Gianotti, Gruppo 1, 25/3/200218 Multiple gauge boson production at SLHC W+W+ W-W- Z* q q Z q q q q W Z Z W Z - Probe  quartic anomalous couplings (e.g. 5-ple vertex = 0 in SM) - Rate limited at LHC Process Expected events after cuts 6000 fb -1 WWW 2600 WWZ 1100 ZZW 36 ZZZ 7 WWWW 5 WWWZ 0.8 W  Z  = e,  LHC sensitive to some 4-ple vertices SLHC may be sensitive to 5-ple vertex Not yet studied at CLIC …

19. Fabiola Gianotti, Gruppo 1, 25/3/200219 FCNC top decays at SLHC t c,u , Z, g Most measurements (e.g.  m top ~ 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) 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 99% C.L. sensitivity to FCNC BR (units are 10 -5 ) only possible if b-tagging performance at SLHC similar to LHC

20. Fabiola Gianotti, Gruppo 1, 25/3/200220  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

21. Fabiola Gianotti, Gruppo 1, 25/3/200221 Higgs couplings to fermions and bosons g Hff Can be obtained from measured rate in a given production channel:  deduce  f ~ g 2 Hff 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  %

22. Fabiola Gianotti, Gruppo 1, 25/3/200222 Higgs self-couplings at SLHC Higgs potential : ~ 3 v m H 2 = 2 v 2  probe HHH vertex via double H production LHC :  (pp  HH) 110 GeV + small BR for clean final states  no sensitivity SLHC : HH  W + W - W + W -   jj  jj studied (very preliminary) S B S/B S/  B m H = 170 GeV 350 4200 8% 5.4 m H = 200 GeV 220 3300 7% 3.8 6000 fb -1 Backgrounds (e.g. tt) rejected with b-jet veto and same-sign leptons If : -- K B 2 < K S -- 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%

23. Fabiola Gianotti, Gruppo 1, 25/3/200223 Higgs self-couplings at CLIC - m H =120 GeV, 4b final states TESLA :  25% precision 1000 fb -1 CLIC :  7 % precision 5000 fb -1 5000 fb -1

24. Fabiola Gianotti, Gruppo 1, 25/3/200224 Higgs rare decays Signal significance S/  B : LHC ~ 3.5 LHC (600 fb -1 ) ~ 3.5 SLHC ~ 11 SLHC (6000 fb -1 ) ~ 11 H  Z    Signal significance S/  B : LHC ~ 3.5 LHC (600 fb -1 ) ~ 3.5 (gg+VBF) SLHC ~ 7 SLHC (6000 fb -1 ) ~ 7 (gg) H   m H =130 GeV Additional coupling measurement: g H  to ~ 15% BR (H   ) ~ 10 -4 SM

25. Fabiola Gianotti, Gruppo 1, 25/3/200225 CLIC, 5000 fb -1 g H  to ~ 5% Higgs rare decays Signal significance S/  B : LHC ~ 3.5 LHC (600 fb -1 ) ~ 3.5 SLHC ~ 11 SLHC (6000 fb -1 ) ~ 11 H  Z    Signal significance S/  B : LHC ~ 3.5 LHC (600 fb -1 ) ~ 3.5 (gg+VBF) SLHC ~ 7 SLHC (6000 fb -1 ) ~ 7 (gg) H   m H =130 GeV Additional coupling measurement: g H  to ~ 15% BR (H   ) ~ 10 -4 SM

26. Fabiola Gianotti, Gruppo 1, 25/3/200226 MSSM Higgs sector : h, H, A, H  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 For m A < 600 GeV, TESLA can demonstrate indirectly (i.e. through precision measurements of h properties) existence of heavy Higgs bosons at 95%C.L. 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 600 fb -1 6000 fb -1 m h < 130 GeV m A  m H  m H 

27. Fabiola Gianotti, Gruppo 1, 25/3/200227 CLIC : sensitive to m (A, H, H  ) up to  1 TeV  full MSSM Higgs spectrum should be observed H+H+ H-H- , Z e+e+ e-e- e.g. H + H - production H   tb  Wbb  jjbb  8 jets final state 3000 fb -1 ttbb backgound  m ~ 4%

28. Fabiola Gianotti, Gruppo 1, 25/3/200228 Strong V L V L scattering at LHC, SLHC If no Higgs, expect strong V L V L scattering (resonant or non-resonant) at q q qq VLVL VLVL VLVL VLVL LHC :   fb Forward jet tag and central jet veto essential tools against background Fake fwd jet tag probability from pile-up (preliminary..) ATLAS full simulation LHC may observe only non-resonant W L W L  W L W L More channels, e.g. W L Z L  W L Z L, Z L Z L  Z L Z L, may be observed at SLHC  more clues to underlying dynamics Need new trackers (e.g. charge measurement)  ~ 280 GeV Pile-up included

29. Fabiola Gianotti, Gruppo 1, 25/3/200229 Strong V L V L scattering at CLIC Observation of strong EWSB not granted at LHC, SLHC: -- only fully leptonic final states accessible  tiny rates -- non-resonant W L W L : 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 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 W  jj W, Z mass resolution ~7% (collimated jets) E.g. expected significance for non-resonant W L W L  W L W L : LHC (300 fb -1 ) ~ 5  SLHC (3000 fb -1 ) ~ 13  K-matrix unitarization model CLIC (1000 fb -1 ) ~ 70 

30. Fabiola Gianotti, Gruppo 1, 25/3/200230  Examples of Physics beyond the SM : -- SUSY -- Extra-dimensions -- Z ’ -- Compositeness

31. Fabiola Gianotti, Gruppo 1, 25/3/200231 SUSY at LHC, SLHC CMS tan  =10 5  contours 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 : LHC  2.5 TeV SLHC  3 TeV  s = 28 TeV, 10 34  4 TeV  s = 28 TeV, 10 35  4.5 TeV 5  discovery reach on -- No major detector upgrade needed for discovery : inclusive signatures with high p T 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)

32. Fabiola Gianotti, Gruppo 1, 25/3/200232 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 Examples of mSUGRA points compatible with present constraints M1M1 M2M2 M 3 = (from LHC) Blair, Porod, Zerwas EW  RGE  GUT from precise measurements of e.g. gaugino masses at EW scale reconstruct theory at high E m 1/2

33. Fabiola Gianotti, Gruppo 1, 25/3/200233 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

34. Fabiola Gianotti, Gruppo 1, 25/3/200234 Arkani-Hamed, Dimopoulos, Dvali If gravity propagates in 4 +  dimensions, a gravity scale M D  1 TeV is possible M Pl 2  M D  +2 R  at large distance SM wall Bulk G G If M D  1 TeV :  = 1 R  10 13 m  excluded by macroscopic gravity  = 2 R  0.7 mm  limit of small- scale gravity experiments ….  = 7 R  1 Fm Extra-dimensions are compactified over R < mm R

35. Fabiola Gianotti, Gruppo 1, 25/3/200235 Gravitons in Extra-dimensions get quantised mass:  continuous tower of massive gravitons (Kaluza - Klein excitations) G f f  Only one scale in particle physics : EW scale Can test geometry of universe and quantum gravity in the lab Due to the large number of G kk, the coupling SM particles - Gravitons becomes of EW strength

36. Fabiola Gianotti, Gruppo 1, 25/3/200236 Supernova SN1987A cooling by emission (IBM, Superkamiokande)  bounds on cooling via G kk emission: M D > 31 (2.7) TeV  = 2 (3) Distorsion of cosmic diffuse  radiation spectrum (COMPTEL) due to G kk   : M D > 100 (5) TeV  = 2 (3) large uncertainties but  =2 disfavoured Seattle experiment, Nov. 2000 R > 190  m M D > 1.9 TeV r

37. Fabiola Gianotti, Gruppo 1, 25/3/200237 1 st example : direct G production in ADD models at LHC/SLHC G q q g  topology is jet(s) + missing E T M D = gravity scale  = number of extra-dimensions 5  reach Expected limits (Tevatron, HERA) in 2007: M D > 2-3 TeV for  =3 SLHC : -- no major detector upgrade needed (high-p T calorimetric objects) -- similar reach for virtual G exchange -- G and  /Z resonances observable up to 5-8 TeV

38. Fabiola Gianotti, Gruppo 1, 25/3/200238 2 nd 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 e+e+ e-e- G M D (TeV) 5 TeV 3 TeV Indirect sensitivity up to ~ 80 TeV (depending on model) through precision measurements

39. Fabiola Gianotti, Gruppo 1, 25/3/200239 3 nd example : Graviton resonance production in RS models at CLIC e+e-  + -e+e-  + - CLIC is resonance factory up to kinematic limit. Precise determination of mass, width, cross-section (from resonance scan `a la LEP1), branching ratios, spin …

40. Fabiola Gianotti, Gruppo 1, 25/3/200240 6 6 Additional gauge bosons : Z ’ Mass can be measured to  % (dominant error: calorimeter E-scale up to ~5 TeV, then statistics) For Z-like Z’ with  (Z’) / m(Z’) ~ 3% direct discovery reach up to ~ 7 TeV LHC, SLHC CLIC 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

41. Fabiola Gianotti, Gruppo 1, 25/3/200241 Contact interactions at LHC, SLHC 14 TeV 3000 fb -1 Quark sub-structure modifies di-jet angular distribution at Hadron Colliders 14 TeV 14 TeV 28 TeV 28 TeV 300 fb -1 3000 fb -1 40 60 60 85 95% C.L. lower limits on  (TeV) If b-tagging available can measure jet flavour

42. Fabiola Gianotti, Gruppo 1, 25/3/200242 Contact interactions at CLIC 1000 fb -1 From EW measurements Sensitive to eeqq, ee  complementary to Hadron colliders Not allowed, couplings diverge ( > 1) Not allowed (EW vacuum unstable, <0) V (  ) =  2 |  | 2 + |  | 4 m H 2 =2 (m Z ) v 2 ~ 115 CLIC  s = 5 TeV can probe  up to ~ 800 TeV

43. Fabiola Gianotti, Gruppo 1, 25/3/200243 SUMMARY LHC upgrades :  s = 14 TeV, L=10 35 (SLHC) : extend LHC mass reach by  30%   7 TeV  s = 28 TeV, L=10 34 : extend LHC mass reach by  50%   8 TeV  s = 28 TeV, L=10 35 : extend LHC mass reach by  2   11 TeV SLHC : -- although some signatures (jets, E T miss, , 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 ?  s = 28 TeV : -- significant improvement of LHC discovery potential -- precision measurements for L = 10 34   however: benefit/cost ratio too small ? 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” ?

44. Fabiola Gianotti, Gruppo 1, 25/3/200244 Units are TeV (except TGC and W L W L 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 3 1.5 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 W L W L 3.0  7.5  70  90  30  TGC  (95%) 0.0014 0.0004 0.0006 0.00013 0.00008 0.0003  compositeness 35 100 50 300 400 130 † indirect reach (from precision measurements) probes directly the 10-100 TeV scale probes indirectly up to 1000 TeV Comparison with TeV LC and VLHC

45. Fabiola Gianotti, Gruppo 1, 25/3/200245 Factory and Muon Collider : a 3-step project Œ Œ factory : -- Superconducting Proton Linac (SPL) : high-intensity p source (10 16 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.  m W  7 MeV,  m top  MeV, H lineshape (  m H  0.1 MeV,  H  0.5 MeV at 115 GeV ) Ž ŽHigh-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 excellent physics potential at each step ! Fundamental questions to be solved for  and  :  cooling (fast ionisation cooling ?) and acceleration (re-circulating LINAC) longertime-scale than CLIC

46. Fabiola Gianotti, Gruppo 1, 25/3/200246 Examples of possible post-LHC scenarii and options (speculative …) 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 10 6 GeV ?  give SUSY a last chance with a VLHC ? LHC finds contact interactions   < 60 TeV   VLHC to probe directly scale  ? LHC finds Extra-dimensions  M D < 15 TeV   VLHC to probe directly scale M D ? 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 ? Note : here LC  Lepton Collider

47. Fabiola Gianotti, Gruppo 1, 25/3/200247 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