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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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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
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
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
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
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
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
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
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
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
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
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
Compact LInear Colliders = 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
“ 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
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
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
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 totot, 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
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
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
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
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
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
~ 3v 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
- 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
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
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
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
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
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
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
Examples of Physics beyond the SM : -- SUSY -- Extra-dimensions -- Z ’ -- Compositeness Fabiola Gianotti, Gruppo 1, 25/3/2002
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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. mW7 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
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
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