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Higgs Physics in CMS A. Nikitenko

Higgs Physics in CMS A. Nikitenko. CERN, Building 40. ATLAS. CMS. Meeting in IPM, April 2009. Layout. Introduction Higgs boson searches In SM In MSSM In Extra Dimensions: Radion-Higgs sector. Introduction. SM Higgs mass constraints from the data and theory. Experiment. SM theory.

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Higgs Physics in CMS A. Nikitenko

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  1. Higgs Physics in CMSA. Nikitenko CERN, Building 40 ATLAS CMS Meeting in IPM, April 2009

  2. Layout • Introduction • Higgs boson searches • In SM • In MSSM • In Extra Dimensions: Radion-Higgs sector

  3. Introduction

  4. SM Higgs mass constraints from the data and theory Experiment SM theory Indirect constraints from precision EW data : MH < 260 GeV at 95 %CL (2004) MH < 186 GeV with Run-I/II prelim. (2005) MH < 166 GeV (2006, ICHEP06) MH < 154 GeV (2008, Physics at LHC 08) The triviality (upper) bound and vacuum stability (lower) bound as function of the cut-off scale L “triviality” : Higgs self-coupling remains finite Direct limit from LEP MH > 114.4 GeV

  5. Tevatron SM Higgs exclusion in 2008 (Physics at LHC , 2008)

  6. 2009 Moriond

  7. NLO Mt from TeV 2005: Mt=172.7+/-2.9 GeV hep-ex/0507091 We use 175 GeV in PTDR

  8. SM Higgs boson couplings and Br. ratios Djouadi, Kalinowski, Spira tree level couplings v is vev of Higgs field = 246 GeV Right bottom plot includes uncertainties from the quark masses mt, mb, mc and as(MZ)

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

  10. Physics runs in 2010:200 pb-1 at 10 TeV First , we should “discover” Standard Model to be prepared for Higgs discovery: QCD jets, W/Z(+jets), tt~, WW, ZZ, ….

  11. ExpectedW->mn at 10 TeV for 10 pb-1

  12. W/Z+nJets one of very important background for Higgs at LHC Zbb,Zcc, Wbb, Wcc are as important as W/Z+nj

  13. I present CMS Higgs physics based on CMS PTDR Vol.2 + updates for “early data”

  14. SM Higgs boson searches Inclusive H->ZZ->4l, H->gg, H->WW->2l VBF qq->qqH, H->tt H->ZZ->ee mm

  15. H->ZZ(*)->4l - golden mode of CMS(first studies in 1995) • Background: tt->WbWb->llnnbb, • ZZ->4l, llbb (“Zbb”) • Selections : • lepton isolation in tracker and calo • lepton impact parameter, mm, ee vertex • mass windows MZ(*), MH H->ZZ->ee mm

  16. H->ZZ->4l • New elements of PTDR analysis: • ZZ background: NLO k factor depends on m4l • background from side bands or from ZZ/Z; (gg->ZZ is added as 20% of LO qq->ZZ, no generator yet) Signal and background at 5 sigma discovery eemm eemm CMS at 5s sign. CMS at 5s sign.

  17. CMS: “early” H->ZZ->4l Exclusion goes much faster than discovery ! PTDR Vol.2: SM H->4m CMS 2009, 1 fb-1 analysis

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

  19. PTDR design

  20. 1, uncert ~ 50%

  21. New elements of PTDR 2006 analysis: - splitting into categories depending of R9=E(3x3)/Esc and h regions - usage of LLR for discovery, systematic - “optimized analysis” – NN with kinematics and g isolation as input, s/b per event 1 fb-1 1 fb-1 barrel with large R9 barrel with small R9 1 fb-1 1 fb-1 endcaps with large R9 endcaps with small R9

  22. Discovery potential of H->gg CMS PTDR 2006 CMS PTDR 2006 SM light h->gg in MSSM inclusive search ECAL TDR 1997 Significance for SM Higgs MH=130 GeV for 30 fb-1

  23. CMS: “early” H->gg re-scaling PTDR Exclusion goes much faster than discovery ! CMS, 14 TeV, 10 pb-1 PTDR Vol.2: SM H->gg CMS, 14 TeV 100 pb-1

  24. Discovery of SM H->gg in associated ttH and WH production at high luminosity Discovery of Wh, h->gg Discovery of tth, h->gg L=1034 cm-2 s-1 L=1034 cm-2 s-1 Significance of tth, h->gg for 100 fb-1

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

  26. Early discovery with H->WW->2l2n ...counting experiment... • New elements of PTDR analysis • PT 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) • 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: - ETmiss > 50 GeV - jet veto in h < 2.4 - 30 <pT l max<55 GeV - pTl min > 25 GeV - 12 < mll < 40 GeV

  27. Discovery reach with H->WW->2l Excluded cross section times Branching Ratio at 95% C.L. CMS Phys. TDR 2006

  28. Updated H->WW analysis1 fb-1 , 14 TeV, 2009 • W+jets bkg. is added • Detector misalignment/miscalibration • more conservative bkg. systematic • Optimized selections for each mass point

  29. Discovery of qqH associated production (Weak Boson Fusion) qq->qq, H->tt

  30. (written in 2005)

  31. 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

  32. First, full simulation analysis ofqqH, H->tt->l+jet (IC) SM discovery light h in MSSM Discovery in Standard Model

  33. CMS: “early” qqH, H->tt-> l+j1 fb-1, 14 TeV, 2008 Exclusion limit

  34. Summary of SM Higgs boson discovery in CMS.

  35. Prospects for SM Higgs for 200 pb-1 at 10 TeV

  36. Searches for MSSM Higgs bosons Mt=172.4+-1.2 GeV MW=80.398+-0.025 GeV

  37. Unconstrained MSSM is the most “economic” version of SUSY • Minimal gauge group SU(3)CxSU(2)LxU(1)Y • Minimal particle content; tree generation of spin ½ quarks and leptons [no right handed neutrino] as in SM; The two Higgs doublets leads to five Higgs particles : two CP even h, H bosons, a pseudoscalar A boson and two charged H+/- bosons • R parity conservation: Rp = (-1)2S+3B+L • Minimal set of soft SUSY-breaking terms • Unconstrained MSSM has 124 free parameres (104 from SUSY breaking terms + 19 parameters of the SM) • Constrained MSSM (or phenomenological MSSM) reduces number of free parameters to 22 • all the soft SUSY-breaking parameters are real => no new source of CP-violation in addition to the one from CKM matrix • no FCNC at tree level • the soft SUSY-breaking masses and trilinear couplings of the 1st and 2nd sfermion generations are the same at low energy • So far most of the MSSM Higgs boson searches at LHC were performed within the framework of phenomenological MSSM (pMSSM) without assuming any particular soft SUSY-breaking scenario (mSUGRA, AMSB, GMSB, ..)

  38. At tree level Higgs sector of MSSM is determined by two parameters: MA and tan(b) tan(b) = v2/v1 = (v sin(b)) / (v cos(b)) where v1 and v2 are vacuum expectation values (vev) of the neutral components of two Higgs doublets. v12+v22 = v2 = 2MZ2 /(g22+g12) = (246 GeV)2 Higgs masses at tree level mH,h2 = ½[ (mA2 +mZ2 ) ± ((mA2 +mZ2)2 – 4mZ2mA2 (cos22b))1/2 ] mH+2 = mA2 + mW2 mh < mZ

  39. Constraints on MSSM Higgs from LEP searches in mhmax scenario From hep-ex/0602042 mt= 169.3 174.3 179.3 183.0 Low tanb is not completely excluded: search for LHC with pp->A; A->Zh, gg, tt High tanb area for search at LHC with pp->bbf (f=h, H, A) and f->mm, tt decays

  40. Light SUSY Higgs in CPX

  41. Neutral Higgs boson couplingsto fermions and gauge bosons in the MSSM at treelevelnormalized to the SM Higgs boson couplings gHff=(21/2Gm)1/2mf, gHVV = (21/2Gm)1/2MV2 and the couplings of two Higgs bosons with one gauge boson, normalized to gW = (21/2Gm)1/2 for gFH+W- and gZ=(21/2Gm)1/2MZ for gFAZ a is a mixing angle between neutral components for two Higgs doublets H10, H20 to give the physical CP-even Higgs bosons h, H cos2a = -cos2b ((MA2-MZ2)/(MH2-Mh2)) Radiative corrections introduce dependence on other parameters : m, M2, Mgluino + 5 “physical” parameters: mstop1,2, msbottom1,2, qstop or m, M2, Mgluino + 5 “unphysical parameters”: mstopL, mstopR, msbottomR, At, Ab

  42. Cross sections for MSSM Higgs bosons production at LHC Xt=61/2MS (mhmax scenario), MS=2TeV, mt=178 GeV, mb(mb)=4.9 GeV; NLO QCD corrections for all channels, but ttF, bbF; mR=mF=1/2(MF+2mt) for ttF and ¼(MF+2mb) for bbF. NLO MRST set of PDF

  43. Heavy CP-odd Higgs boson (A) branching ratios

  44. CMS reach for MSSM neutral Higgs bosons • pp->bbf (f->h, H, A) – high tanb • f->mm • f->tt • pp->A at low tanb • A->Zh • Z->ll (l=e, m) • h->bb

  45. pp->bbf, f->mm Discovery reach at low MA, “intensive coupling” and decoupling regimes h+A H+A h+H+A Possible constraint on tanb by measuring width of A/H->mm

  46. bbf, f->2t analysistwo t-jets is most challenging topology t jet1 t jet2 b jet1 b jet2

  47. H/A->2t->ll, l+j, jj analyses Selections include single b tagging, thus selecting gg->bbA/H production process mtt with e/m+j and j+j modes after selections

  48. Z->tt as benchmark for H->ttmass reconstruction b(b)Z as benchmark for b(b)H Monte Carlo, NLO QCD, b-PDF

  49. MSSM neutral Higgs bosons: TeV vs LHC CMS prospects for 5s discovery Phys TDR 2006 CDF+D0 prospects

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