CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 1

ttH(120), H ttH(120), H bb bbttH(120), H ttH(120), H bb bb

U. of Maryland

Shuichi Kunori

15-June-2001

CMS Note 2001/xxx

D.Green, K.Maeshima, R.Vidal, W.Wu, S.Kunori

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 2

SM HiggsSM HiggsSM HiggsSM Higgs

gg fusion WW/ZZ fusion

associatedHtt

associated WH, ZH

production decay

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 3

1 iso. lepton (PT>10GeV) 6 jets (4 b tag) (ET>20GeV) -> max. likelihood (b likeliness, W mass, top mass …)

MH=115 GeV

Bg: ttbb, ttjj, ttZ0

Mass(jj)

MH

5

30fb-1

mistagging probability (%)

m/m=3.8% (stat)

bb

(V.Drollinger)

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 4

1 iso. lepton (e,) (PT>20GeV)

only 2 jets (b-tag) (ET>30GeV)MT(W) -> events in higgs mass window

MH=115 GeV

Bg: Wjj, tt, tb

5

300fb-1

bb

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 5

CouplingsCouplingsCouplingsCouplings

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 6

ttHttHttHttH

Final state:

t Wb lbt Wb jjbH bb

1 isolated leptonMET6 jets (ET>20GeV) - 4 b-tags

CompHEP V41.10CMGEN CompHEP-PYTHIA interface V46 PYTHIA 6.157 b-tag simulator for pre-selectionCMSIM 120Analysis cone jet finder

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 7

# of Jets (E# of Jets (ETT>20GeV)>20GeV)# of Jets (E# of Jets (ETT>20GeV)>20GeV)

ttH ttHw/o em cluster

ttbb ttbbw/o em cluster

Minimum 5 jets4 b-tagged

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 8

Leading Jets & leptonLeading Jets & leptonLeading Jets & leptonLeading Jets & lepton

ttH

ttbb

ttZ

L1 Trigger:

1 lepton + ET(jet)>100GeV

HLT

b-tag

100GeV

0 200 400 GeV

Offline:

only one loosely isolated lepton, i.e.

(ETcone-ET

lep)/ETcone<0.5

PT>20GeV in ||<2.5

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 9

Mass in ttH sampleMass in ttH sampleMass in ttH sampleMass in ttH sample

qq(W)

qqb(top)

lb(W)

bb(H)

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 10

Kinematics VariablesKinematics VariablesttH (solid) ttbb (dash)ttH (solid) ttbb (dash)Kinematics VariablesKinematics Variables

ttH (solid) ttbb (dash)ttH (solid) ttbb (dash)

M(tbb) (t-bb)

y(t-bb)

R(t-bb)

Ry(t-bb)

*(b-bb)At bb rest system

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 11

y distributiony distributionttH(solid), ttbb(dash), ttZ(dot)ttH(solid), ttbb(dash), ttZ(dot)

y distributiony distributionttH(solid), ttbb(dash), ttZ(dot)ttH(solid), ttbb(dash), ttZ(dot)

|y| < 1

CMS HCAL/JetMET @ CERN, 15-June-2001 S.Kunori 12

Mass(bb)Mass(bb)for ttH + ttbb + ttZfor ttH + ttbb + ttZ

Mass(bb)Mass(bb)for ttH + ttbb + ttZfor ttH + ttbb + ttZ

Particle level

CMSIM

|y|<1.0

|y|<1.0

No y cut

No y cut

S/B 1/2 ~11.8

(S/B ~1/1)

Need good b-tagging !