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THE LHC/LC SYNERGY

THE LHC/LC SYNERGY. S. Dawson, BNL December, 2002 Why we need both the LC and the LHC Examples: EWSB, SUSY, top quark The cosmological connection. Why are we here?. Not to compare/ contrast LHC/LC

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THE LHC/LC SYNERGY

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  1. THE LHC/LC SYNERGY S. Dawson, BNL December, 2002 • Why we need both the LC and the LHC • Examples: EWSB, SUSY, top quark • The cosmological connection

  2. Why are we here? • Notto compare/ contrast LHC/LC • Rather to see how physics info from one machine can influence physics results from the other • Goal: Working group document, Spring 03 Weiglein, Oreglia

  3. What do we want to know? • What is the origin of EWSB? • Is it a Higgs? • Is it something else? • What is the origin of fermion masses? • Understanding the top quark • Is there physics at an intermediate scale? (and what is the scale?) • Is it SUSY? • Is it little Higgs? • Is it extra dimensions? • …..

  4. Is mass due to a Higgs boson? Precision measurements: • Production rates at LEP, Tevatron, LHC fixed in terms of mass • Direct search limit from LEP • Higgs contributions to precision measurements calculable G. Mylett, Moriond02

  5. Higgs Discovery at Tevatron or LHC LHC Tevatron Carena, Conway, Haber, Hobbs, hep-ph/0010338 ATLAS TDR

  6. How do we verify role in EWSB? Measure Yukawa couplings Measure spin/parity Reconstruct Higgs potential Is it a Higgs?

  7. LHC measures B Eg, ggh depends on ggh and h couplings Result is combination of coupling constants Significant PDF uncertainties Cancel in ratios Weak boson fusion depends on SU(2) assumption about WWh and ZZh couplings Precision measurement for Mh>140 GeV from WBF Higgs properties at LHC Zeppenfeld, Belyaev, Reina

  8. Mh<140 GeV, H/H10-20% Not all channels possible tth, h+- critical Higgs Measurements at LHC 200 fb-1 300 fb-1 (tth,h, Wh,hbb) Belyaev & Reina, hep-ph/0205270

  9. PDF uncertainties cancel in ratios Improved precision by fixing bbh/h coupling to SM value Note lousy precision on bbh Theory systematic error: 20% (ggh) 5% (WBF) 10% (pptth) Untangle Higgs Couplings 200 fb-1 Belyaev & Reina, hep-ph/0205270

  10. Well determined initial state Precision masses with recoil technique Higgs mass independent of Higgs decay Model independent Higgs BRs Van Kooten

  11. Coupling Constant Measurements at LC LC Compare LHC: gbbh40-50% WBF, 600 fb-1 gbbh 10-20% Piccinini & Polosa, hep-ph/0211170 At LC, largest uncertainty is theory from mb! L=500 fb-1, s=350 GeV Battaglia & Desch, hep-ph/0101165

  12. Who cares about Higgs Couplings?And how well do we need to do? • SUSY models, gbbh enhanced at large tan , small MA …info about SUSY parameters • Little Higgs, topcolor models, new physics in gtth Logan

  13. LC: LHC: Direct reconstruction of LC @ 350 Gev Higgs mass measurements Primarily interesting for comparison with precision EW measurements Conway, hep-ph/0203206

  14. Angular correlations of decay products distinguish scalar/pseudoscalar Threshold behavior measures spin Higgs spin/parity in e+e-Zh [20 fb-1 /point] Miller, hep-ph/0102023

  15. Higgs self couplings difficult at LHC gghhW+W-W+W-(jjl)(jjl) ghhh=Mh2/2v Baur, Plehn, Rainwater, hep-ph/021124

  16. Must measure e+e- Zhh Small rate .2 fb for Mh=120 GeV large background Large effects in SUSY Resonances ghhh suppressed MA < 300 GeV Measuring Higgs Self Couplings at LC Castanier, Gay, Lutz, Orloff, hep-ph/0101028 Lafaye, hep-ph/0002238

  17. Is the world Supersymmetric? Find SUSY particles Find SUSY partners Check impact on precision measurements Measure SUSY couplings Reconstruct underlying GUT theory

  18. SUSY predicts light Higgs, Mh<130 GeV For MA, SUSY Higgs sector looks like SM Can we tell them apart? Higgs BR are different in SUSY Find all SUSY Higgs Light SUSY consistent with Precision Measurements

  19. Find all the Higgs Bosons Tevatron LHC  collider sensitive 4 years at ! Carena, hep ph/9907422 Gunion

  20. e+e- H+H-, H0A0 Observable to MH=460 GeV at s=1 TeV e+e- H+,H+tb L=1000 fb-1, s=500 GeV, 3 signal for MH 250 GeV e+e- W+H- Largest at low tan  s=500 GeV, .01 fb Moretti, hep-ph/0209210 Into the wedge Logan & Su, hep-ph/0206135

  21. mSUGRA simplest version of SUSY • 4 parameters, 1 sign • m0 (scalar mass at MGUT) • m1/2 (gaugino mass at MGUT) • A0 (mixing term) • tan  (ratio of Higgs VEVs) Measure m(gluino) at LHC predict m(neutralino) at LC Very predictive…all masses and couplings predicted Relationships are different for GMSB, AMSB…..

  22. SUSY mass differences from cascade decays;eg M0 limits extraction of other masses Fit to SUGRA parameters LHC/Tevatron will find SUSY Baer Catania, CMS

  23. Chargino pair production, S-wave Rises steeply near threshold This example: LC makes precision mass measurements How do we distinguish a chargino from a 4th generation lepton? Feng, hep-ph/0210390 Blair, hep-ph/99910416

  24. LC mass measurements from endpoint spectra

  25. LC can step through Energy Thresholds Run-time Scenario for L=1000 fb-1 • SUSY masses to .2-.5 GeV from sparticle threshold scans • M0/M0 7% (Combine with LHC data) • 445 fb-1 at s=450-500 GeV • 180 fb-1 at s=320-350 GeV (Optimal for Higgs BRs) • Higgs mass and couplings measured, gbbh1.5% • Top mass and width measured, Mt150 GeV Battaglia, hep-ph/0201177

  26. LHC: Fits to SUSY Parameters LHC: Mass reconstruction limited by LSP mass  LHC sensitive to mass differences Bachacou, Hinchliffe, Paige, hep-ph/9907518 LC accuracy Measurement of LSP mass at LC improves LHC mass resolution

  27. SUSY: LC+LHC • LHC sensitive to heavy squarks • Use neutralino mass, couplings from LC • CMS study:10 fb-1 gives squark, gluino masses to 1-2% if neutralino mass known from LC R. Van Kooten: “Bands, not blobs”

  28. LC measures chargino, neutralino, selectron masses from thresholds LC extracts mixing parameters from cross section measurements LHC measures gluino, squark masses RGE evolve parameters to GUT scale Sample mass measurements (SPS#1A): LC: LHC: Combine LC/LHC mass measurementsWindow to high scales?

  29. Do gaugino & Scalar masses unify in mSugra? Scalar masses Gaugino masses Freitas, hep-ph/0211076

  30. Compare rates at NLO: Lowest order, Super-oblique corrections sensitive to higher scales Masses from endpoints Assume Tests coupling to 1% with 20 fb-1 SUSY Couplings: Feng Probes mechanism of SUSY breaking

  31. Are we being too simplistic? • Many possibilities beyond MSSM • Suppose explicit CP violation • Complex tri-linear mixing • Instead of h,H, and A  3 states which mix • Holes in LEP limits on Higgs search • New phenomenology Carena, Mrenna

  32. LC/LHC can give insight into origin of dark matter SUSY provides dark matter candidate, LSP LSP is weakly interacting, neutral and stable Cosmic Connections

  33. mSUGRA predicts everything in terms of 5 parameters Calculate 0 relic density Assume 2 around central value Assume Dark Matter is 0  Forbidden by 3 g-2 .07 <Xh2<.21 Requires m1/2>300-400 GeV M(+)>240 GeV M(o)>120 GeV Arnowitt and Dutta, hep-ph/0204187

  34. CLEO bound from bs Similar allowed region from dark matter Does this picture persist for more complicated SUSY models? Dark Matter at large tan  1.8 x 10-4<B(bs) <4.5 x 10-4

  35. Understanding the Top Quark • Why is Mtv/2 ? • Kinematic reconstruction of tt threshold gives pole mass at LC • Compare LHC  2Mt (GeV) Groote , Yakovlov, hep-ph/0012237 QCD effects well understood NNLO ~20% scale uncertainty

  36. Precision Mt, MW test consistency of SM Limits Higgs mass, SUSY parameters Who cares about precision Mt?

  37. tth coupling sensitive to strong dynamics Above tth threshold e+etth Theoretically clean s=700 GeV, L=1000 fb-1 Large scale dependence in tth rate at LHC L=300 fb-1 Top Yukawa coupling tests models Baer, Dawson, Reina, hep-ph/9906419 Juste, Merino, hep-ph/9910301 Reina, Dawson, Orr, Wackeroth, hep-ph/0211438 Beenacker, hep-ph/0107081

  38. tth at LC • 20 % measurement of gtth to mh=200 GeV using hWW decay • Needs s=800 GeV Gay, 02

  39. Still have to understand MW, precision measurements Fit to S, T0 Without Higgs, effective theory For new physics at 3 TeV scale, EW fits give a,b1 Models which satisfy EW constraints without Higgs tend to have new Z’ or light t’s What if the LHC doesn’t find a Higgs???? Bagger, Falk, & Schwartz, hep-ph/9908327 Hill & Simmons, hep-ph/0203079

  40. Exciting physics ahead • LHC/Tevatron finds Higgs LC makes precision measurements of couplings to determine underlying model • LHC finds evidence for SUSY, measures mass differences LC untangles spectrum, finds sleptons LHC/LC combination makes precision measurements of couplings and masses; Untangles GUT theory

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