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Linear Collider Physics

Linear Collider Physics. We need the LHC asap, for lots of very good reasons. We need 2 L C s. The TeV I nternational L inear C ollider, also asap. Then a multi-TeV C L I C. + (maybe) a Larger Hadron Collider.

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Linear Collider Physics

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  1. Linear Collider Physics David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  2. We need the LHC asap, for lots of very good reasons. Weneed 2 LCs The TeV International Linear Collider, also asap. Then a multi-TeV CLIC + (maybe) a Larger Hadron Collider David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  3. The TeV ILC planned for 2015, overlaps with LHC. Parametersdefined by ILCSC scope-panel for ITRP http://www.fnal.gov/directorate/icfa/LC_parameters.pdf Baseline s =200-500 GeV, integrated Luminosity 500 fb-1 over 1st 4 years 80% electron polarisation 2 interaction regions with easy switching Upgrade Anticipate s  1 TeV, L= 1 ab-1 over 4 years Options e-e- collisions, 50% positron polarisation, “GigaZ”; high L at Z and at WW threshold, Laser backscatter for  and e collisions, Doubled Lat 500 GeV. Choice among options to be guided by physics needs. ITRP wants highest possible David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  4. Physics case for LHC has been made and accepted. It will look into the whole region where new physics should be. Physics AND cosmology say “expectstrong new signals at the scale of 1 TeV”. Physics case for the TeV ILC has been made. (LCWS series, TESLA TDR, JLC/GLC reports, Snowmass black book, European+ACFA+ALCPG workshops etc. etc. + work in progress; see LHC/LC Study Group report athttp://www.ippp.dur.ac.uk/~georg/lhclc/). At least 2700 physicists support ILC (http://sbhep1.physics.sunysb.edu/~grannis/lc_consensus.html) I will present some of the case here. (Or see Peskin at Victoria 31 July; http://www.linearcollider.ca:8080/lc/vic04/plenary/m_peskin.pdf) Physics cases for CLIC (and Larger HC?) will follow results from LHC and TeV ILC. David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  5. 1. Definite; mt<100MeV 2. If there is a light Higgs • If LHC sees nothing new • below ~ 500 GeV mass 3. and extra particles Programme for the TeV ILC • will depend on what appears, but ILC is • needed in every scenario . David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  6. Recent illustration; D0’s new mtmeasurement 2001; mt=174.3 5.1; PDG 2004;mt=178.0 4.3 Moves best fit mh by > 20 GeV. Very sensitive. 1. Definite job to be done. Measure mt to <  100 MeV Why? Because precision on mtlimits current SM fit. David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  7. current MW Precise mt championed by Heinemeyer et al (hep-ph/0306181, and LHC/LC report) A couple of their examples a) What it does for The Standard Model  “Unless mt < 100MeV, it is the dominant error on many precision measurements.” David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  8. b) what precise mt would do for MSSM (Heinemeyer et al) David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  9. Can we get mt < 100MeV with a real ILC ? We think so. Doing R&D on spectrometry and detector-based measurement. Lots of work for ITRP – see Victoria workshop: Barklow, Torrens, Woods, DJM: http://www.linearcollider.ca:8080/lc/vic04/abstracts/detector/ipbi/ E.g. new work by Boogert* on fitting mtat threshold with beamstrahlung and Initial State Radiation, using Bhabha acollinearity+. Realistic fit gives shift of mtby only 48 Mev; can surely correct to ~ 10 MeV *reported by DJM at http://www.linearcollider.ca:8080/lc/vic04/abstracts/physics/topqcd/; + Frary+DJM, Kurihara et al, Cinabro, Moenig. David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  10. 2. If there is a light Higgs of any kind, seen or unseen at LHC. The ILC will see it and pin it down. Does it have standard model couplings? What is its precise mass? Does it have light scalar partners? Many scenarios investigated (see LHC/LC report etc.) David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  11. Higgs mass measurement (TESLA TDR; newer work confirms) 500 fb-1 at 350 GeV Constrained fits to final states David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  12. Precision on Higgs branching ratios with LC and  TESLA TDR David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  13. For new work on combined LHC/LC see next slide top Yukawa Sphicas Vienna TESLA TDR c.f. Sphicas Vienna 2004, for LHC. Both machines needed to get complete picture. David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  14. - Direct tthwith ILC at ~ 800 GeV makes a big difference tth Mh s (GeV) New work on top Yukawa coupling Dawson, Juste, Reina and Wackeroth, LHC/LC report. Branching ratios and couplings from 500 GeV ILC improve LHC result Mh Mh - 600 800 David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  15. Higher precision can give discoveries. If ILC measures the wrong Higgs mass (using S.M. fits with ILC value of mt) it has discovered the new physics. LHC precision on mh may not be enough to do this. Cosmic Microwave Background WMAP constrains WL+WM Then Wouldn’t know it’s there from COBE AND Planck is coming; more precise still Now WITH Polarisation David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  16. If there is a light Higgs • and extra particles E.g. the Minimal Supersymmetric Standard Model*, then LHC expects to see squarks and gluinos. ILCgood for sleptons and especially for Lightest Supersymmetric Particle ( LSP is favoured candidate for Dark Matter). New studies at point SPS1a in LHC/LC report (Martyn). LC at s=400 GeV, L= 200 fb-1. Clear endpoints give, for example, (some others come from threshold scans). lepton energy (GeV) *(+ new work on NMSSM and others in LHC/LC report, at Victoria, here) David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  17. * * * + * * + * * - - + + + Global fits to MSSM (LHC/LC report, Lafaye, Plehn and D.Zerwas) * Needs > 500 GeV. (Also<500 study in LHC/LC) + e+e- threshold scan. - e-e- threshold scan (s-wave allowed) LC alone, ~1/100 of LHC error on LSP David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  18. SUSY Partners in e-e- and e- - the natural habitat of the selectron • Dotted lines are perfect beams • Solid for flat beams with ISR, • beamstrahlung, and energy spread. • Dashed is for round beam e-e-. • Need 1/100 luminosity in • e-e- compared with e+e- • to measure selectron mass • to 100 MeV. • Similar big • cross-section advantages in S wave David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  19. Sensitivity of pMSSM parameters to experimental inputs (Lafaye, for SPA project, Beijing 17/8/04) David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  20. IF we have a self consistent SUSY picture, can extrapolate fundamental couplings in mSUGRA (say) to the GUT scale, via renormalisation group equations. LC+ GigaZ solid bands, LHC outer lines. Allanach, Blair, Kraml, Martyn, Polesello, Porod,Zerwas LC constrains more tightly at GUT scale. David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  21. Global fits to MSSM (LHC/LC report, Lafaye, Plehn and D.Zerwas) Combined  ½  error from LC alone. Uses dilepton mass from LHC (see next). LC alone, ~1/100 of LHC error on LSP David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  22. But look-out! Warning from Michael Peskin at Victoria. Sharp edge gives mass (CMS study) mll “The differences between these scenarios are very subtle. But they are the whole game.” LC can confirm which one it is. David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  23. If LHC sees nothing new • below ~ 500 GeV mass Peskin again, at Victoria: David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  24. (Lots being done about these in the LHC/LC study) David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  25. David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  26. em David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  27. - (e+e-  f f ) ILC (direct) Sensitivity to heavy Z’ in different models ILC includes GigaZ (Z-Z’ mixing) and 1 TeV LC (interference) [Richard, hep-ph/0303107] David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  28. Or WLWL Resonances; LHC sees direct up to ~1.5 TeV 1.9 TeV resonance parameters; above direct threshold for both colliders. LC 1 TeV 1 ab-1 LHC fit, 100fb-1 500 GeV 500 fb-1 Imposing a1=1(S.M. coupling) get blue bar from LHC, red from ILC. e+e- WW scattering amplitudes sensitive even to Low Energy Theorem effects. 15 s.d. for 1.9 TeV resonance. (Barklow, Snowmass) ILC resolves single resonance from LET point up to 2.5 TeV (s = 500), 4.1 TeV (s = 1000 GeV). Well beyond LHC David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  29. ILClooks beyond LHC’s direct reach Then LHC + ILC point to CLIC, and maybe superLHC Summary of the case for the TeV ILC 1. Definite; mt<100MeV • If LHC sees nothing new • below ~ 500 GeV mass Vital constraint. Increasingly sure it can be done. 2. If there is a light Higgs LHC probably sees. ILCshows what it is. LHC and ILC needed to pin down model, identify DM(?), extrapolate to GUT scale. 3. and extra particles David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  30. EWSB 2004. Is there a structure here? David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  31. EWSB 2010. It’s taking shape. L H C David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  32. EWSB L H C L C 2015. Looks like a gateway! David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  33. EWSB L H C L C 2020. Both pillars needed to see to the Temple of Unification David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

  34. David J. Miller UCL; Linear Collider Physics. ICHEP Beijing 22/8/04

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