Analysis status for heavy charged Higgs with H +

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Analysis status for heavycharged Higgs with H+

R.Kinnunen, S. LehtiHelsinki Institute of Physic, Helsinki

Higgs WG MeetingCERN, 23 October, 2007

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Contents:

- Workplan and status for fully hadronic gg->tbH+, H+

- Background analysis for 100 fb-1 with W-> in tt and W+jet events

- Background analysis for 100 fb-1 with QCD events

- ”Hard reconstruction” in the signal events

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Off-line event selection

• Veto on isolated electrons and muons, pT >~ 10-20 GeV/c

• MET > 100 GeV

• jet reconstruction, ET > 100 GeV

• isolation: no track with pT > 1 GeV/c in the isolation cone of 0.04 < R < 0.4 around the leading track

• Electron rejection: At least one HCAL cell with ET > 2 GeV in the jet

• One-prong selection:

– One reconstructed track in the signal cone

– ptrack / E jet > 0.8

• Three-prong selection:

– Three reconstructed tracks in the signal cone

– Matching between ET(CALO cluster) and pTtrack to select ->

– ptrack / E jet > 0.8 or ptrack / E jet < 0.4

• Tagging of one b jet and top mass reconstruction

• Transverse mass reconstruction from jet and MET

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Backgrounds for gg->tbH+, H+

Main background processes: tt, W+3jets, QCD multi-jet eventsIn ideal case, - signal at large mT( jet,MET), with an endpoit at mT( jet,MET) ~ mH+

- backgrounds from W-> (tt, W+jets) distributed to mT( jet,MET) < mW

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Sources background in the signal area

Background in the signal area (mT( jet,MET) > 100 GeV) can be devidedinto 3 gategories:

• Diffusion of background events to the signal area due to MET measurement - This background in tt and W+jets events can be measured with muons from W-> decays in tt and W+jets events - Background due to QCD multi-jet events can be measured in QCD events measuring fake probability in other processes

• Fake jets due to difficulty of the identification Could be measured from data exploiting + jet events as proposed in CMS NOTE-2006/028

• Fake leading tracks (pT > 80 GeV) Can be reduced with strong quality cuts, studies going on (PFlow group), L. Wendland for ’s in gg->tbH+, H+

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

• Isolated electron veto to suppress W->e in tt events• One muon with pT

> 100 GeV• Muon isolation• ET

miss > 100 GeV• 3 jets, ET > 20 GeV• W+3jet selection: no b jets, suppression of tt • tt selection: 2 b jets, suppression of W+3jets• mT(,MET) reconstruction

Background analysis for 100 pb-1 in muon events

Event selection:1. Single muon trigger2. Off-line selection cuts:

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Background in the signal area can be estimates through:

Ntt-sel = (Ntt

-sel – NW3jcont) * (/) * (

-sel/ sel )* top rec.

-sel / b-tag

Nw3j-sel = (Nw3j

-sel – Nttcont) * (/) * (

-sel/-sel)* top rec.

-sel * b-tag / (b-antitag)

NW3jconand NW3j

conarethe W+3jet and tt contamination to tt and W+3jet selections

: to be estimated from MC not enough events from Z-> -> jet in this energy scale

MET( sel.): MET efficiency in signal (jet) selectionMET( sel.): MET efficiency in background (jet) selection

b-tag : to be measured in b enriched tt events

b-antitag : can be measured from +jet events, if fraction of +b events is below 1%

- top reconstruction: to be checked if affects the shape of the mT( jet, ET

miss) distribution

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Event selection:• Events from tau + MET trigger• At least one jet with pT

jet > 100 GeV• One of the jets with pT

jet > 100 GeV taken randomly as candidate• ET

miss > 100 GeV• 3 jets, ET > 20 GeV • one ”b” jet• top mass reconstruction• mT( candidate,MET) reconstruction

Background analysis for 100 pb-1 in QCD events

Events in the signal area:

NQCD(-sel) NQCD(QCD-sel) * miss-id)

miss-id) can be measured in +jet events

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Software version and data samples

- CMSSW version CMSSW_1_6_7 used

- Data samples used:

tt: tt0j_mT_70-alpgen, = 840 pbW+3 jets: W3jet_0ptw100-alpgen, 0 < pT

W < 100 GeV, = 588 pb W+4 jets: W4jet_0ptw100-alpgen, 0 < pT

W < 100 GeV, = 124 pb QCD: QCD_Pt_120_170, 120 < pT

jet < 170 GeV Signal: RelVal160pre8ChargedHiggsTausM200 mH+ = 200 GeV, 5000 events

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Muons from reco::MuonCollection - tracker isolation in a cone of R=0.3 and pT

cut = 1 GeV used

Muon off-line selection

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

MET reconstruction

reco::CaloMET used including muons from reco::MuonCollectionNo MET corrections yet

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

B tagging

JetTagCollection: trackCountingHighPurJetTags

2 tagged b jets, ET(jet) > 20 GeV, discriminator > 1.5 (not optimized yet)

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Expected behaviour from MC variables in tt events

Transverse mass mT(,MET) distributions

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Transverse mass mT(,MET) distributionsPreliminary results for tt, t1->b,t2->hadrons

Unnormalized distributions

Events in the signal area were wound to originate mainly from real neutrinosfrom W-> originating from the secod top-need to implement -jet veto in the muon selection and second veto in the signal selection

W2-> and W2->eremoved with MC info

tail due to MET resolution

Some events from W->

MET should originatefrom W->

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Transverse mass mT(,MET) distributionsPreliminary results for W+3jet, W->

All remaining events at large mT are signal-like with well measured MET

Originate from the BW tail of the W need to genetate the W mass in bins to study the effect

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

- Select jets passing the the IsolatedTauTagInfoCollection with ET > 100 GeV Parameters for the IsolatedTauTagAlgo: pT

leading track > 20 GeV, R(match) =0.1, R(signal)=0.07, R(isol) = 0.45, pT(min) = 1 GeV

- Require matching with the MC jet from gg->tbH+, H+

- Definition of energy resolution: ETjet / ET

visible MC -1

- Event sample used: RelVal160pre9ChargedHiggsTausM200 - small statistics, 5000 events !

First tentative for a ”hard algorithm”

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Visible hadronic

mH+ = 200 GeV

ET(MC jet)

MC jet)

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Possible algorithm of reconstructing large ET one-prong ’s R. Kinnunen and A. Nikitenko

for good geometrical ECAL-HCAL-track matching do following: 1. If |ET

HCAL+ECAL - pTtrack| < 2 CALO: use ~ track p, corresponds to ±

2. If ETHCAL+ECAL – pT

track > 2 CALO 2.1 if |ET

HCAL - pTtrack| < 2 HCALuse ~ track p + ECAL cluster,

corresponds to ±n with charged pion not interacting in ECAL 2.2 if pT

track - ETHCAL > 2 HCAL ±interaction in ECAL, take the calo jet

2.3 if ETHCAL - pT

track > 2 HCAL hadronic jet, reject

- Optimization of the cones forenergy collection in ECAL and HCAL needed

2.1) 2.2)

±±

HCAL

ECAL

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Definition: ETcalo cluster / pT

track – 1 Calo cluster reconstruction from CaloRecHits withR(ECAL impact point, cell) < 0.1 in ECALR(ECAL impact point, cell) < 0.2 in HCAL

One prong decay mode without neutrals,-> h

Test CALO cluster/track matching for one-prong ’s

Almost all events withinETcalo cluster / pT

track – 1| < 0.5

Matching variable

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Calo cluster/track matching forn

Test here the HCAL cluster/track matching

pjet ~ ptrackBad track ?reject

Matching variables

III

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Loss of energy observed, try to minimize the effect with an asymmetric cut:

- 0.5 < ETcalo cluster / pT

track – 1 < 0.2

candidates with Calo Cluster/track matchingregion II

Energy resolution forn

Energy resolution forwith Calo Cluster/track matching

Resolutions

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

HCAL cluster/track matching:add the ECAL cluster to include 0’s

±interaction in ECAL, take the calo jet

Hadronic jet: reject

HCAL cluster/track matching fornRegion III

Select large window |ET

HCAL cluster / pTtrack – 1 |< 0.8

due to energy loss in this area

Matching variables

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Comparison with reco::Jet

Resolutions

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

All one-prong ’s selected with MC info

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Conclusions and plans

1) Background analysis with W-> in tt and W+3jet events and in QCD events in progress Large mass tail observed in mT(,MET): - mainly due to W-> in tt events - due to natural W width in W+3jet events

2) First results from a ”hard -tau” algorithm for one-prong ’s in gg->tbH+,

H+ with ET-jet > 100 GeV were presented

- Improvement of jet resolution possible with a simple algorithm

• New group members: Katri Lassila, fake probability from +jet events Matti Kortelainen, top mass reconstruction, Benedict Hegner should join

later Richard Cavanaugh, with PFlow, MET

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

Backup slides

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

const CaloJet* caloJet = dynamic_cast<const CaloJet*>(&(iTau->jet()));

vector<CaloTowerRef> towers = caloJet->getConstituents();

for(vector<CaloTowerRef>::const_iterator iTower = towers.begin(); iTower != towers.end(); iTower++){

// access CaloRecHits for(size_t j = 0; j < numRecHits; j++) { DetId recHitDetID = (**iTower).constituent(j);

DetId::Detector detNum=recHitDetID.det();

if( recHitDetID.det() == DetId::Ecal ){ if( recHitDetID.subdetId() == 1 ){ // Ecal Barrel

EBDetId ecalID = recHitDetID; EBRecHitCollection::const_iterator theRecHit = EBRecHits->find(ecalID);

if(theRecHit != EBRecHits->end()){ DetId id = theRecHit->detid();

const CaloCellGeometry* this_cell = EB->getGeometry(id); if(this_cell){

GlobalPoint hitPos = this_cell->getPosition(); double eta = hitPos.eta(); double phi = hitPos.phi();

double theta = hitPos.theta(); if(theta > 3.14159) theta = 2*3.14159 - theta;

// ecalCells.push_back(hitPos); double energy = theRecHit->energy();

double et = energy * sin(theta); Double_t px = energy * sin(theta)*cos(phi); Double_t py = energy * sin(theta)*sin(phi); Double_t pz = energy * cos(theta);

4. EBRecHit4. EBRecHit

Higgs WG meeting, 23 October 2007R. Kinnunen, S. Lehti

5. ECAL impact point

- using TransientTrack

const TransientTrack transientTk = (transientTrackBuilder->build(&(leadTk)));

- ecalHitPosition is taken as maxTowerEt position

TrajectoryStateClosestToPoint TSCP = transientTk.trajectoryStateClosestToPoint(ecalHitPosition);

GlobalPoint trackEcalHitPoint = TSCP.position();