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Super-LHC

Super-LHC. Albert De Roeck CERN & Antwerp University. The LHC Machine and Experiments. LHCf. (MOEDAL). pp collisions at 14 TeV. totem. The LHC: 22 Years Already!. 1984. /LHC. 1984: cms energy 10-18 TeV Luminosity 10 31 -10 33 cm -2 s -1 1987: cms energy 16 TeV

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Super-LHC

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  1. Super-LHC Albert De Roeck CERN & Antwerp University

  2. The LHC Machine and Experiments LHCf (MOEDAL) pp collisions at 14 TeV totem

  3. The LHC: 22 Years Already! 1984 /LHC 1984: cms energy 10-18 TeV Luminosity 1031-1033cm-2s-1 1987: cms energy 16 TeV Luminosity 1033-1034cm-2s-1 Final: cms energy 14 TeV Luminosity 1033-1034cm-2s-1

  4. The LHC Progress & Schedule • The LHC Schedule(*) • LHC will be closed and set up for beam on 1 September 2007 • LHC commissioning will take time! • First collisions expected in November/December 2007 • A short pilot run • Collisions will be at injection • energy ie cms of 0.9 TeV • First physics run in 2008 ~ 0.1-1 fb-1? 14TeV! • Physics run in 2009 +… 10-20 fb-1/year 100 fb-1/year Crucial part: 1232 superconducting dipoles Can follow progress on the LHC dashboard http://lhc-new-homepage.web.cern.ch/lhc-new-homepage/ More than 1000 dipoles installed by now (*) eg. M. Lamont et al, September 2006. Achtung! Lumi estimates are mine, not from the machine

  5. 2007-2008 Ramping up the LHC hypothetical luminosity scenario J. Strait 2003: Not an “official” LHC plot Statistical error1/N Constant luminosity/year 1 year4 years16 years to half the stat error Luminosity= #events/cross-section/time If startup is as optimistic as assumed here (1034 cm-2s-1 in 2011 already) After ~3 years the simple continuation becomes less exciting Time for an upgrade?

  6. The LHC upgrade Already time to think of upgrading the machine if wanted in ~10 years Two options presently discussed/studied • Higher luminosity ~1035cm-2 s-1 (SLHC) • Needs changes of the machine and particularly of the detectors •  Start change to SLHC mode some time 2014-2016 •  Collect ~3000 fb-1/experiment in 3-4 years data taking. • Discussed in this talk • Higher energy? (DLHC) • LHC can reach s = 15 TeV with present magnets (9T field) • s of 28 (25) TeV needs ~17 (15) T magnets  R&D needed! • Even some ideas on increasing the energy by factor 3 (P. McIntyre)

  7. Machine Upgrade Studies 626 2002 Report on a machine study • Upgrade in 3 main Phases: • Phase 0 – maximum performance without hardware changes • Only IP1/IP5, Nb to beam beam limitL = 2.31034cm-2s-1 • Phase 1 – maximum performance while keeping LHC arcs unchanged • Luminosity upgrade (*=0.25m,#bunches,...)L = 5-101034cm-2s-1 • Phase 2 – maximum performance with major hardware changes to the LHC • Energy (luminosity) upgrade  Ebeam = 12.5 TeV

  8. nominal and ultimate LHC baseline upgrade 25 ns back-up upgrade 12.5 ns Bunch schemes for SLHC plus: large luminosity gain with minimal event pile up & impact of c more & shorter bunches concern: e-cloud, cryogenic load, LRBB, impedance, collimation, machine protection plus: large luminosity gain with no e-cloud, lower I, easier collimation & machine protection fewer & longer bunches concern: larger event pile up, impedance 75 ns plus: no e-cloud, lower I abandoned super-bunch concern: event pile up intolerable

  9. IP Upgrade Triplet moves closer to IP Dipole inside end disks? Possible scenario: magnets in the detectors

  10. Machine Parameters 1035cm-2s-1 peak luminosity seems possible Bunch crossing somewhere between 12.5 75 ns March 2006

  11. Machine Upgrade Studies Studies in the context of the CARE HHH Network HHH = High Energy High Intensity Hadron-Beam facilities in Europe http://care-hh.web.cern.ch/CARE-HHH/ Step 4 requires a new RF system Step 5: upgrade LHC cryogenics, collimation, beam dump systems… Further possible paths: flat beams, dipoles close to IP, crab cavities… Challenging but bigger challenges on the detector side

  12. LHC SLHC s 14 TeV 14 TeV Luminosity 1034 1035 Bunch spacing t 25 ns 12.5/75 ns pp (inelastic) ~ 80 mb ~ 80 mb N. interactions/x-ing ~ 20 ~ 100/600 (N=L pp t) dNch/d per x-ing ~ 150 ~ 750/4500 <ET> charg. particles ~ 450 MeV ~ 450 MeV Tracker occupancy 1 5/30 Dose central region 1 10 Detectors for SLHC • The present detectors need to be upgraded to cope with the higher occupancy and • radiation • Detector R&D program Normalised to LHC values. 104 Gy/year R=25 cm In a cone of radius = 0.5  ET ~ 80GeV from pile up. This will make low Et jet triggering and reconstruction difficult. Academic training lectures http://agenda.cern.ch/fullAgenda.php?ida=a056409

  13. Pile up… HZZ  ee event with MH= 300 GeV for different luminosities 1032 cm-2s-1 1033 cm-2s-1 1034 cm-2s-1 1035 cm-2s-1

  14. Example of Detector Upgrades Tracker detector of both CMS & ATLAS will need to be replaced  Occupancy, radiation Include the tracker in the L1 trigger? • Study, detector R&D and production takes time! • Possible scenario: Proceed in two steps • Include new layers in the present tracker during the LHC running • Upgrade to full new tracker system by SLHC (8-10 years from LHC Startup)  ATLAS & CMS upgrade workshops since ~two years ..

  15. Detectors Upgrades for SLHC • Modest upgrade of ATLAS, CMS needed for channels with • hard jets, , large ETmiss • Major upgrades (new trackers ..) for full benefit of higher L: • e ID, b-tag, -tag, forward jet tagging, trigger upgrade e.g • a tracking trigger…  Study Physics Potential of the LHC • Detector Performance Assumed • Performance at L = 1035cm-2s-1 is comparable to that at 1034cm-2s-1 !! • Some know degradations taken into account in individual analyses • Integrated Luminosity per Experiment • 1000 (3000) fb-1 per experiment for 1 (3) year(s) of at L = 1035cm-2s-1. • Pile-up added • Corresponding to 12.5 bunch crossing distance scenario

  16. Extending the Physics Potential of LHC • Electroweak Physics • Production of multiple gauge bosons (nV 3) • triple and quartic gauge boson couplings • Top quarks/rare decays • Higgs physics • Rare decay modes • Higgs couplings to fermions and bosons • Higgs self-couplings • Heavy Higgs bosons of the MSSM • Supersymmetry • Extra Dimensions • Direct graviton production in ADD models • Resonance production in Randall-Sundrum models TeV-1 scale models • Black Hole production • Quark substructure • Strongly-coupled vector boson system • WLZL g WLZL , ZLZL scalar resonance, W+LW +L • New Gauge Bosons Examples studied in some detail Include pile up, detector… hep-ph/0204087

  17. W W g, Z Standard Model Physics • Precision measurements of Standard Model processes and parameters • Deviations of expectations can point to new physics or help to understand new observed phenomena TGCs Rare top decays Higgs …

  18. W W g, Z Triple/Quartic Gauge Couplings Triple gauge couplings: W,WZ production Production of multiple gauge bosons: statistics limited at LHC E.g. # events with full leptonic decays, Pt>20 GeV/c, ||<2.5, 90% eff for 6000 fb-1 Typically gain of a factor of 2 in precision

  19. Top Quark Properties SLHC statistics can still help for rare decays searches Results in units of 10-5 Ideal = MC 4-vector Real = B-tagging/cuts as for 1034cm-2s-1 -tag = assume only B-tag with muons works at 1035cm-2s-1 tq tqZ Can reach sensitivity down to ~10-6 BUT vertex b-tag a must at 1035cm-2s-1

  20. The Higgs at the LHC (SM) • First step • Discover a new Higgs-like particle at the LHC, or exclude its existence • Second step • Measure properties of the new particle to prove it is the Higgs • Measure the Higgs mass • Measure the Higgs width • Measure cross sections x branching ratios • Ratios of couplings to particles (~mparticle) • Measure decays with low Branching ratios (e.g H) • Measure CP and spin quantum numbers (scalar particle?) • Measure the Higgs self-coupling (HHH), in order to reconstruct the Higgs potential LHC~1 good year of data SLHC added value Only then we can be sure it is the Higgs particle we were looking for

  21. gHff Channel mH S/B LHC S/B SLHC (600 fb-1) (6000 fb-1) H  Z   ~ 140 GeV ~ 3.5 ~ 11 H   130 GeV ~ 3.5 (gg+VBF) ~ 9.5 (gg) Higgs Decays Modes Rare Higgs Decays gH/gH? Channels studied:  H  Z    H   Branching ratio ~ 10-4 for these channels! Cross section ~ few fb Higgs Couplings (ratios) Can be improved with a factor of 2: 20%10% at SLHC

  22. ~ v mH2 = 2  v2 Higgs Self Coupling Measurements Once the Higgs particle is found, try to reconstruct the Higgs potential Djouadi et al. Dawson et al. /2 << 3/2 Difficult/impossible at the LHC

  23. Higgs Self Coupling Baur, Plehn, Rainwater HH  W+ W- W+ W-   jj jj Limits achievable at the 95% CL. for =(-SM)/SM LHC: = 0 can be excluded at 95% CL. SLHC:  can be determined to 20-30% (95% CL) For MH ~ 150 -180 GeV Note: Different conclusion from ATLAS study no sensitivity at LHC and smaller sensitivity at SLHC. Jury is still out

  24. Lower Higgs Masses Baur, Plehn, Rainwater • ppbb not useable • ppbb promising •  For mH=120 GeV and 600 fb-1 • expect 6 events at the LHC • with S/B~ 2 (single b tag) • Potentially interesting measurement at the SLHC (if efficient b-tagging ) mvis Needs accurate prediction of the bb background rate Experimental checks needed

  25. SUSY Higgses h,H,A,H In the green region only SM-like h observable with 300 fb-1/exp Red line: extension with 3000 fb-1/exp Blue line: 95% excl. with 3000 fb-1/exp Heavy Higgs observable regionincreased by ~100 GeV at the SLHC.

  26. Beyond the Standard Model New physics expected around the TeV scale  Stabelize Higgs mass, Hierarchy problem, Unification of gauge couplings, CDM,… Supersymmetry Extra dimensions +… + a lot of other ideas… Split SUSY, Little Higgs models, new gauge bosons, technicolor, compositness,..

  27. 5 contours CMS tan=10 Supersymmetry Reach: LHC and SLHC Impact of the SLHC Extending the discovery region by roughly 0.5 TeV i.e. from ~2.5 TeV  3 TeV This extension involved high ET jets/leptons and missing ET  Not compromised by increased pile-up at SLHC

  28. SLHC: tackle difficult SUSY scenarios Squarks: 2.0-2.4 TeV Gluino: 2.5 TeV Can discover the squarks at the LHC but cannot really study them Pt >700 GeV & Etmiss>600 GeV Pt of the hardest jet eg. Point K in hep-ph/0306219 signal Exclusive channel qq 10 10 qq S/B =120/30 (3000fb-1) Higgs in 2 decay 21h becomes Visible at 3000 fb-1 Inclusive: Meff> 4000 GeV S/B = 500/100 (3000 fb-1) ~~ Measurements of some difficult scenarios become possible at the SLHC

  29. Extra Dimension Signals at the LHC example Graviton production! Graviton escapes detection Large (ADD) type of Extra Dimensions Signal: single jet + large missing ET escape! About 25% increase in reach

  30. SLHC: KK gravitons Randall Sundrum model  Predicts KK graviton resonances  k= curvature of the 5-dim. Space  m1 = mass of the first KK state TeV scale ED’s  KK excitations of the ,Z T.Rizzo SLHC 95% excl. limits Direct: LHC/600 fb-1 6 TeV SLHC/6000 fb-1 7.7 TeV Interf:SLHC/6000 fb-1 20 TeV 1001000 fb-1:Increase in reach by 25%

  31. New gauge bosons  SLHC 1000 fb-1  LHC 100 fb-1 LHC reach ~ 4.0 TeV with 100 fb-1 ~ 1.0 TeV Gain in reach ~ 1.0 TeV i.e. 25-30% in going from LHC to SLHC

  32. Spin analysis (Z’RS gravitons) Luminosity required to discriminate a spin-1 from spin-2 hypothesis at the 2 level  May well be a case for the SLHC  Also: SUSY particle spin analysis (Barr, Webber, Smiley) need > 100 fb-1

  33. q q VL VL VL q VL q Strongly Coupled Vector Boson System If no Higgs, expect strong VLVL scattering (resonant or non-resonant) at • Could well be difficult at LHC. What about SLHC? • degradation of fwd jet tag and central jet veto due to huge pile-up • BUT : factor ~ 10 in statistics  5-8 excess in W+L W+L scattering •  other low-rate channels accessible

  34. WZ vector resonance in VB scattering Vector resonance(ρ-like) in WLZL scattering from Chiral Lagrangian model M = 1.5 TeV300 fb-1 (LHC) vs 3000 fb-1 (SLHC) lepton cuts: pt1 > 150 GeV, pt2 > 100 GeV, pt3 > 50 GeV; Etmiss > 75 GeV These studies require both forward jet tagging and central jet vetoing! Expected (degraded) SLHC performance is included At LHC: S = 6.6 events, B = 2.2 events At SLHC: S/B ~ 10

  35. Indicative Physics Reach Ellis, Gianotti, ADR hep-ex/0112004+ updates Units are TeV (except WLWL reach) Ldt correspond to 1 year of running at nominal luminosity for 1 experiment • PROCESS LHCSLHC DLHC VLHCVLHC LC LC • 14 TeV14 TeV 28 TeV 40 TeV 200 TeV 0.8 TeV 5 TeV • 100 fb-11000 fb-1 100 fb-1 100 fb-1100 fb-1 500 fb-1 1000 fb-1 • Squarks 2.534 5200.4 2.5 • WLWL24 4.5 7 18 6 90 • Z’ 56811 358†30† • Extra-dim (=2) 91215 25 655-8.5† 30-55† • q* 6.57.5 9.5 13 750.8 5 • compositeness 3040 40 50100 100 400 TGC () 0.00140.0006 0.0008 0.0003 0.0004 0.00008 † indirect reach (from precision measurements) Approximate mass reach machines: s = 14 TeV, L=1034 (LHC) : up to  6.5 TeV s = 14 TeV, L=1035 (SLHC) : up to  8 TeV s = 28 TeV, L=1034 (DLHC) : up to  10 TeV

  36. Summary: LHC Upgrade The LHC luminosity upgrade to 1035 cm-2s-1 In general: SLHC gives a good physics return for “modest” cost, basically independent of the physics scenario chosen by Nature  It is a natural upgrade of the LHC  Extend the LHC discovery mass range by 25-30% (SUSY,Z’,EDs,…)  Higgs self-coupling measurable with a precision of (20-30%)  Rear decays accessible: H, Z, top decays…  Improved Higgs coupling ratios by a factor of 2,…  TGC precision measurements… •  It will be a challenge for the experiments! • Needs detector R&D starting now: Tracking, electronics, trigger, endcaps, radiation, shielding… •  CMS and ATLAS have working groups/workshops on SLHC The energy upgrade DLHC is certainly more costly and up in the future

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