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
Fabiola Gianotti, Gruppo 1, 25/3/20022 Outline of Savings Plan 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, 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, 25/3/20023 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 has to stay within budget - review ongoing
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
Fabiola Gianotti, Gruppo 1, 25/3/20025 Possible options for future machines LHC upgrade : luminosity (L = cm -2 s -1 ), maybe energy ( s = 28 TeV ? ) TeV-range e + e - LC (TESLA, NLC, JLC) : s = 0.5 –1.5 TeV, L = cm -2 s -1 multi-TeV e + e - LC (CLIC) : s = 3-5 TeV, L = cm -2 s -1 Muon Collider : s 4 TeV, L ~ – cm -2 s -1 ? Three steps : factory, Higgs factory, high-E muon collider VLHC : s = TeV, L = 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
Fabiola Gianotti, Gruppo 1, 25/3/20026 LHC upgrade Discussions started in Spring 2000 : -- luminosity upgrade to L = 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, 25/3/20027 From preliminary feasibility studies : L upgrade to : -- increase bunch intensity to beam–beam limit L ~ 2.5 x 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 ?
Fabiola Gianotti, Gruppo 1, 25/3/20028 s = 28 TeV upgrade L = 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)
Fabiola Gianotti, Gruppo 1, 25/3/20029 L = : 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) cm / / /28 190/ /10 70/ /2 7/ /1 2/11 CMS tracker ECAL dose HCAL dose (kGy) (kGy) /18 0.2/ /120 4/ / / / /6000 CMS calorimeters —— 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/ Trackers : need to be replaced (radiation, occupancy, response time) -- R > 60 cm : development of present Si strip technology ~ ok < 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/ 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 e/jet separation: L (cm -2 s -1 ) Electron efficiency Jet rejection % % 6800 1130 E T = 40 GeV b-tagging : (GeV) pTpT Rejection against u- jets for 50% b-tagging efficiency assuming same 2-track resolution at as at Full Geant simulation No optimisation done deterioration smaller at higher E
Fabiola Gianotti, Gruppo 1, 25/3/ Compact LInear Collider s = 3 5 TeV, L = 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 MV/m achieved with 3 ns bunch trains CTF3 ( ) : 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/ 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) L in 1% s 56 % 30% 25% L in 5% s 71 % 42% 34% TESLA-like detector under study: 3-15 cm Si VDET cm Si central/ forward disks cm TPC or Si tracker cm ECAL cm HCAL cm Coil (4T) cm Fe/muon Event rates/year 3 TeV 5 TeV 1000 fb evts 10 3 evts e + e - tt 20 7 e + e - bb 11 4 e + e - ZZ e + e - W + W e + e - H (120 GeV) e + e - H + H - (1 TeV) e + e - (1 TeV) “ beamstrahlung” Need flavour tagging, calo granularity, etc. But what about E-flow for high-E jets ?
Fabiola Gianotti, Gruppo 1, 25/3/ 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
Fabiola Gianotti, Gruppo 1, 25/3/ 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, = 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 : %
Fabiola Gianotti, Gruppo 1, 25/3/ % C.L. constraints for 1 experiment 14 TeV 14 TeV 28 TeV 28 TeV 100 fb fb -1 Z k k Z g 1 Z (units are ), = 10 TeV from fits to tot, p T , p T Z Z kZkZ Z 14 TeV 100 fb TeV 100 fb TeV 1000 fb 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)
Fabiola Gianotti, Gruppo 1, 25/3/ 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)
Fabiola Gianotti, Gruppo 1, 25/3/ 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 …
Fabiola Gianotti, Gruppo 1, 25/3/ 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 , which are at the limit of the LHC sensitivity Expected limits from Tevatron Run II in 2007 : BR < CLIC : no sensitivity (~ tt pairs/year) Channel LHC SLHC (600 fb -1 ) (6000 fb -1 ) t q t qg t qZ % C.L. sensitivity to FCNC BR (units are ) only possible if b-tagging performance at SLHC similar to LHC
Fabiola Gianotti, Gruppo 1, 25/3/ 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/ 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 %
Fabiola Gianotti, Gruppo 1, 25/3/ 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 % 5.4 m H = 200 GeV % 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%
Fabiola Gianotti, Gruppo 1, 25/3/ Higgs self-couplings at CLIC - m H =120 GeV, 4b final states TESLA : 25% precision 1000 fb -1 CLIC : 7 % precision 5000 fb fb -1
Fabiola Gianotti, Gruppo 1, 25/3/ 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 ) ~ SM
Fabiola Gianotti, Gruppo 1, 25/3/ 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 ) ~ SM
Fabiola Gianotti, Gruppo 1, 25/3/ 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 fb -1 m h < 130 GeV m A m H m H
Fabiola Gianotti, Gruppo 1, 25/3/ 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%
Fabiola Gianotti, Gruppo 1, 25/3/ 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
Fabiola Gianotti, Gruppo 1, 25/3/ 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
Fabiola Gianotti, Gruppo 1, 25/3/ Examples of Physics beyond the SM : -- SUSY -- Extra-dimensions -- Z ’ -- Compositeness
Fabiola Gianotti, Gruppo 1, 25/3/ 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, 4 TeV s = 28 TeV, 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)
Fabiola Gianotti, Gruppo 1, 25/3/ SUSY at CLIC Sensitive to ~ all sparticles up to m ~ TeV can complete SUSY spectrum: some sparticles not observable at LHC (small S/B) nor at TESLA (if m > 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
Fabiola Gianotti, Gruppo 1, 25/3/ 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/ 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 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
Fabiola Gianotti, Gruppo 1, 25/3/ 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
Fabiola Gianotti, Gruppo 1, 25/3/ 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 R > 190 m M D > 1.9 TeV r
Fabiola Gianotti, Gruppo 1, 25/3/ 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
Fabiola Gianotti, Gruppo 1, 25/3/ 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
Fabiola Gianotti, Gruppo 1, 25/3/ 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 …
Fabiola Gianotti, Gruppo 1, 25/3/ 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 – from resonance scan indirect reach from precise (~ %) EW measurements up to ~ 40 TeV
Fabiola Gianotti, Gruppo 1, 25/3/ 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 fb % C.L. lower limits on (TeV) If b-tagging available can measure jet flavour
Fabiola Gianotti, Gruppo 1, 25/3/ 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
Fabiola Gianotti, Gruppo 1, 25/3/ 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 = 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 TeV -- complementary to LHC, SLHC, VLHC almost “ no-lose theorem” ?
Fabiola Gianotti, Gruppo 1, 25/3/ 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 fb fb fb fb fb -1 Squarks Sleptons Z’ 5 8 † 6 20 † 30 † 30 q* * Extra-dim ( =2) † † † 65 W L W L 3.0 7.5 70 90 30 TGC (95%) compositeness † indirect reach (from precision measurements) probes directly the TeV scale probes indirectly up to 1000 TeV Comparison with TeV LC and VLHC
Fabiola Gianotti, Gruppo 1, 25/3/ Factory and Muon Collider : a 3-step project 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) ~ (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 ) 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 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
Fabiola Gianotti, Gruppo 1, 25/3/ 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
Fabiola Gianotti, Gruppo 1, 25/3/ 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