1. Searches for the Standard Model Higgs boson at LHC A. Nikitenko, IC, London. On leave from ITEP, Moscow ICHEP2006, EW session, July 28, 2006 CERN, Building 40 CMS ATLAS

2. Emphasize will be given to the new CMS PTDR results obtained at L=2x10 33 cm -2 s -1 http://cmsdoc.cern.ch/cms/cpt/tdr/ CERN/LHCC 2006-001 CERN/LHCC 2006-021 Published printed in July 2006

3. LHC : 27 km long 100m underground General Purpose, pp, heavy ions CMS +TOTEM ATLAS Heavy ions, pp ALICE pp, B-Physics, CP Violation

4. The CMS Detector today at point 5 The ATLAS Barrel Toroid. End of November 2005

5. SM Higgs mass constraints from the data and theory Indirect constraints from precision EW data : M H < 260 GeV at 95 %CL (2004) M H < 186 GeV with Run-I/II prelim. (2005) M H < 166 GeV (2006) Experiment SM theory The triviality (upper) bound and vacuum stability (lower) bound as function of the cut-off scale  “triviality” : Higgs self-coupling remains finite Direct limit from LEP: M H > 114.4 GeV

6. NLO

7. SM Higgs boson couplings and Br. ratios v is vev of Higgs field = 246 GeV Right bottom plot includes uncertainties from the quark masses m t, m b, m c and  s (M Z ) tree level couplings Djouadi, Kalinowski, Spira

8. Discovery of the inclusive Higgs boson production with decay modes:Discovery of the inclusive Higgs boson production with decay modes: –H->ZZ->4l –H->  –H->WW->2l

9. H->ZZ (*) ->4 l - golden mode (first studies in CMS in 1995) Background: tt, ZZ, ll bb (“Zbb”) Selections : - lepton isolation in tracker and calo - lepton impact parameter, , ee vertex - mass windows M Z(*), M H H->ZZ->ee 

10. H->ZZ->4l New elements of analysis: –ZZ background: NLO k factor depends on m 4l –background from side bands or from ZZ/Z; (gg->ZZ is added as 20% of LO qq->ZZ, no good generator yet) Signal and background at 5 sigma discovery ee  CMS at 5  sign. CMS

11. H->ZZ->4l Signal significance: new vs old results; no big change ~ 125 GeV

12. CP property with H->ZZ->4l d  (  ) ~ H +  I +  2 A, H scalar, A – pseudoscalar,  =tan(  ),  = +/-  /2 --> A C 2 =  Br /  SM Br SM C 2 needed to exclude SM h CMS

13. Inclusive H->  CMS plot of the ECAL TDR time : December 1997 Went then from hybrid silicon + gas chamber tracker to all silicon tracker to all silicon tracker

14. CMS CMS

16. Discovery potential of H->  SM light h->  in MSSM inclusive search CMS ECAL TDR CMS ECAL TDR CMS PTDR CMS PTDR ATLAS ATLAS NLO NLO count. exp NLO NLO cut based NLO NLOoptimized* TDR (LO) New, NLO Cut based New, NLO likelihood ~ 7.5 6.0 6.0 8.2 8.2 3.9 3.9 6.3 6.3 8.7 8.7 Significance for SM Higgs M H =130 GeV for 30 fb -1 * NN with kinematics and  isolation as input, s/b per event

17. Discovery of SM H->  in associated ttH and WH production at high luminosity Discovery of Wh, h->  Discovery of tth, h->  Significance of tth, h->  for 100 fb -1 L=10 34 cm -2 s -1 CMS

18. Accuracy of the Higgs boson mass measurement with H->ZZ->4l and H->  Stat. error only

19. Early discovery with H->WW->2l2 Early discovery with H->WW->2l2 New elements of analysisNew elements of analysis –P T Higgs and WW bkg. as at NLO (re-weighted in PYTHIA) –include box gg->WW bkg. –NLO Wt cross section after jet veto Backgrounds from the data (and theory)Backgrounds from the data (and theory) –tt from the data; uncertainty 16% at 5 fb -1 –WW from the data; uncertainty 17% at 5 fb -1 –Wt and gg->WW bkg from theor. uncertainty 22% and 30% after cuts: - E T miss > 50 GeV - jet veto in  < 2.4 - 30 <p T l max <55 GeV - p T l min > 25 GeV - 12 < m ll < 40 GeV

20. Discovery reach with H->WW->2l Excluded cross section times Branching Ratio at 95% C.L. CMS Phys. TDR 2006 very similar to old results w/o syst.

21. Luminosity needed for 5  discovery for incl. Higgs boson production

22. Discovery of qqH associated production (Weak Boson Fusion) qq->qqH

23. (written in 2005)

24. Jet veto (“rapidity gap”) in VBF (WW->H) production first discussed in : Yu. Dokshitzer, V. Khoze and S. Troyan, Sov.J.Nucl. Phys. 46 (1987) 712 Yu. Dokshitzer, V. Khoze and T. Sjostrand, Phys.Lett., B274 (1992) 116 From D. Zeppenfeld; talk on TeV4LHC, 2004

25. First, full simulation analysis of qqH, H->  ->l+jet Discovery in Standard Model discovery of light h in MSSM in MSSM CMSSM

26. Summary of SM Higgs boson discovery: Signal Significance for 30 fb -1 with K factors ATLAS h->  sensitivity is now comparable with CMS CMS ttH, H->bb does not have even 3  with 60 fb -1

27. ATL-PHYS-PUB-2003/030 Measurement of the SM Higgs boson couplings

28. Conclusions The latest simulation studies show:The latest simulation studies show: –Inclusive h->2  could be discovered with 2  could be discovered with < 10fb -1 –almost no change in the discovery potential with H->ZZ->4l and H->WW->2l. H->ZZ->4l and H->WW->2l. –tth, h->bb is lost as CMS discovery channel even with 60 fb -1 –qqh, h->  “survived” after full simulation ! The biggest discovery reach in M A -tan  –Mass measurement 0.1-1.0 % precision –Width measurement 10-5 % precision, M H > 200 GeV –CP with H->ZZ –Ratio of couplings: ~ 5-30 %

29. BACKUP

30. discrepancy from the SM for light h M. Duhrssen et al.,hep-ph/0407190 Can MSSM be distinguished from SM in the area of only light Higgs discovery ?

31. Total weight 12500 t Overall diameter 15 m Overall length 21.6 m

33. Physics runs 2008-2009 First, we should “discover” Standard Model

34. ~ 10 7-8 Z->ll, W->l on tape during physics run in 2008-09 (~ 10fb -1 ?) Z, W, tt cross sections and expected number of events after trigger in CMS with 10 fb -1 with 10 fb -1 W/Z+nJ+X NLO predictions at LHC with cuts : p T l > 15 GeV |  l | < 2.4 p T j > 20 GeV |  j | < 4.5  R l j > 0.4  R ll > 0.2 W/Z bb + X |  b | < 2.5 J. Campbell, R.K. Ellis, D. Rainwater hep-ph/0308195 ~ 10 6 tt->  +X with 10 fb -1

35. W/Z+nJets is very important background for Higgs at LHC topology Background for Higgs channel (one example) W+1j+Xgg->h->WW*->2l W+2j+X MSSM gg->bbH, H->  -> l +jet (one b-tag) W+3j+X VBF qq->qqh, h->  -> l +jet + 2 tag. jets W+4j+X VBF qq->qqh, h->WW-> l jj + 2 tag jets Z+1j+X MSSM gg->bbH, H->  ->l+jet (one b-tag) Z+2j+X VBF qq->qqh, h->  -> l +jet + 2 tag jets Z+4j+X VBF qq->qqh, h->ZZ-> ll jj + 2 tag jets Zbb,Zcc, Wbb, Wcc (W/Z+QQ+nj) are as important as W/Z+nj

36. Discovery potential for the Higgs boson(s) in CMS is updated in comparison withDiscovery potential for the Higgs boson(s) in CMS is updated in comparison with Higgs Summary Note, CMS Note 2003 : Higgs Summary Note, CMS Note 2003 : –Latest trigger table –Bkg estimates from “data” and exp. systematics –Advanced generators for multi-jet events: ALPGEN, MadGraph, CompHEP, TopRex –almost all analyses use full G4 simulation data

37. New elements of PTDR 2006 analysis: - splitting into categories depending of R 9 =E(3x3)/E sc and  regions - splitting into categories depending of R 9 =E(3x3)/E sc and  regions - usage of LLR for discovery, systematic - usage of LLR for discovery, systematic - “optimized analysis” – NN with kinematics and  isolation as input, - “optimized analysis” – NN with kinematics and  isolation as input, s/b per event s/b per event barrel with large R 9 barrel with small R 9 endcaps with large R 9 endcaps with small R 9 1 fb -1