Update on H→WW→2μ2ν Oct. 8, 2010

IFCA – U. Oviedo

• The work is going on in the HWW and WW analysis (focusing muons in the final state)

• We keep ourselves synchronized• The list of Task proposed during last meeting is almost completely

covered:

Monte Carlo Trigger Tag and Probe Fake Rates Jet Veto Top tagging Drell-Yan estimation

• Plus Multivariate Techniques (BDT) in WW and HWW

Introduction

Rebeca Gonzalez Suarez (08/10/2010) 2

WW synchronization• The μμ channel was already synchronized:

Rebeca Gonzalez Suarez (08/10/2010)

Cuts Guillelmo Dima UspT > 20/20, |h|<2.4 , q1*q2<0 906 906 906

d0 862 862 862

Isolation 749 749 749ID 694 695 695

Conversion rejection 694 695 695tcMET > 20 561 562 562

Minv > 12 558 559 559

| Minv - 91.1876| > 15 417 418 418

Projected tcMET > 20 && tcMET > 45 203 204 204PF Jet Veto (ET > 20 && |h| < 3.0) 136 137 137

Soft muon veto 135 136 136Extra Lepton Veto 135 136 136

3

WW synchronization

Rebeca Gonzalez Suarez (08/10/2010)

Cuts ee ee (us) eμ eμ (us)pT > 20/20, |h|<2.4 , q1*q2<0 1955 1955 2544 2544

d0 1651 1651 2329 2329

Isolation 803 803 1513 1513ID 629 629 1299 1299

Conversion rejection 599 599 1280 1280tcMET > 20 490 490 1034 1034

Minv > 12 490 490 1028 1028

| Minv - 91.1876| > 15 384 384 1028 1028

Projected tcMET > 20 && tcMET > 45 171 171 883 883PF Jet Veto (ET > 20 && |h| < 3.0) 112 112 615 615

Soft muon veto 111 111 613 613Extra Lepton Veto 111 111 613 613

4

• Also synchronized in ee and eμ:

Updated selection for WW

• Some changes were proposed for the WW analysis:– Use of a tighter cut in the projected MET– Open the η of the jets from 3 to 5– Muon PT range from 20/20 to 10/20 (2 regions)

• The HWW analysis is planned to go as close as possible the the WW analysis : – We don’t use the projected MET (yet, will be studied)– The PT range in Higgs is already 10/20– We can implement the change in the η of the jets

considered for the CJV (that should be identical)

Rebeca Gonzalez Suarez (08/10/2010) 5

Effect of the proposed selection

Rebeca Gonzalez Suarez (08/10/2010)

Cuts V 0.0 V 1.0Muon Selection 695 922

tcMET > 20 562 763Minv > 12 559 753

| Minv - 91.1876| > 15 418 592

Projected tcMET > 20/35 && tcMET > 45 204 258PF Jet Veto (ET > 20 && |h| < 3/5) 137 179

Soft muon veto 136 178Extra Lepton Veto 136 178

Gain of ~ 30% for signal

Monte-Carlo WW Spring10 sampleBaseline WW analysis (WW sample, μμ channel)

6

The new selection in perspective

Rebeca Gonzalez Suarez (08/10/2010)

Cuts WW WW (new)

tt tt(new)

Zμμ Zμμ(new)

Muon Selection 242.44 321.63 2771.54 3641.17 347921.00 395905.00tcMET > 20 196.05 266.16 2561.38 3379.31 13463.90 16549.8

Minv > 12 195.00 262.67 2557.98 3362.60 13462.50 16548.4

| Minv - MZ| > 15 145.81 206.51 1947.60 2634.21 2047.84 3449.89

Projected tcMET && tcMET 71.16 90.00 1272.73 1597.50 63.73 61.60PF Jet Veto 47.79 62.44 11.74 12.53 1.42 0

Soft muon veto 47.44 62.09 10.44 10.70 0.71 -Extra Lepton Veto 47.44 62.09 9.92 9.92 0.71 -

Normalizing to 1fb-1 @ 7TeVFor WW signal and some of the main processes to be studied

30% better in signal, similar for top and effective against ZμμWith 100pb-1, it will mean the selection of more than one signal event (~6), with < 2 events of background

7

Status of the HWW analysis

Rebeca Gonzalez Suarez (08/10/2010)

Following WW direction:Muon selection becomes identical (10/20)Same MET (Track corrected)Same Jets for the Central Jet Veto (PF, |η| < 5, ET

RAW > 20)

Test of the cut evolution3.1pb-1

QCD, W+jets, Z+jets, top, WW, WZ, ZZ, tW included

8

Cross-sections × BR (leptons) for Higgs signal < 1 pb (NNLO) selection efficiencies of the analysis at muon selection level are < 10% (for μμ) : with 10 pb-1 at muon selection < 0.9 Higgs events (160) expected in this channel

MH σ×BR (pb-1)

120 0.25

130 0.45

140 0.65

150 0.79

155 0.84

160 0.90

165 0.87

170 0.81

175 0.75

180 0.68

190 0.50

200 0.42

Kinematical distributions

Rebeca Gonzalez Suarez (08/10/2010)

Everything in good shapeStill far from the start of the real the work here3.1 pb-1

After CJV

9

Trigger Studies

Rebeca Gonzalez Suarez (08/10/2010) 10

Some examples for 2E31 trigger Menu, performed with 3.9.0.pre5 RelVal samples in next slide (with tt Fastsim, no HWW available)lowest unprescaled: HLT_Mu11 HLT_Ele17_SW_CaloEleId_L1R high eff. for dilepton final states

Would like to study new triggers in 1E32 table samples?

Electron and muon triggers systematically checked for each table once samples are availableCheck results can be found in the twikihttps://twiki.cern.ch/twiki/bin/viewauth/CMS/HiggsWGHLTValidateAnd in the offline DQM GUIDQMGUI ExampleNext: 1032

Waiting for Higgs to WW samples

Rebeca Gonzalez Suarez (08/10/2010) 11

HLT_Mu11

HLT_Ele17_SW_CaloEleId

Efficiency definition: fraction of selected events passing HLT requirement (top selection eμ)

Trigger EfficienciesEfficiency Vs η and PT

Tag and Probe

Rebeca Gonzalez Suarez (08/10/2010) 12

Tag:- GlobalMuonPT- TrackerMuon- HLT_Mu9- |η| < 2.1- pT > 20 GeV- |d0 | < 0.2- Isolated- GM normalized χ2 < 10- At least one pixel hit- Segments matched in at least 2 muon stations - At least one muon hit matched to the global fit- Number of tracker hits > 10

Probes:Tracks with pT > 5 GeV

Passing probes:- GlobalMuonPT - TrackerMuon- |h| < 2.4- pT > 20 GeV

- |d0 | < 0.02 - Isolated- At least one muon hit matched

to the global fit- Number of tracker hits > 10

12

Zmm VBTF cuts

Monte Carlo: Zmumu Summer10 sampleWith all certified data up to now: 4.43 pb-1

(/Zmumu/Summer10-START36_V9_S09-v1/GEN-SIM-

RECO)

Muon ID + Iso

13Rebeca Gonzalez Suarez (08/10/2010)

Efficiency of the Muon ID + isolation cuts, obtained in data Vs Monte-Carlo, as a function of the PT of the ‘Probe’

And as a function of the η of the ‘Probe’

Trigger Efficiency using T&PTrigger efficiency defined as the fraction of muon fulfiling all the muonID + Isolation criteria and matching a HLT_Mu9 object

Data: MC:

14Rebeca Gonzalez Suarez (08/10/2010)

• The work started with the very early data• Last time we presented this:

• It was a single muon rate measured in data with less than 15 nb-1 using tracks

• The data available and the Monte Carlo were in agreement

Fake Rates

Rebeca Gonzalez Suarez (08/10/2010) 15

Higgs contribution to MUO-10-002

l+d method• For WW and Higgs to WW, we have a method extensively

studied in the CSA07 context oriented to the estimation of the W+jets background in di-muon final states

• Well known and documented:CMS AN 2008/039

• Several talks about it available, for example (8 June): – http://indico.cern.ch/contributionDisplay.py?contribId=2&confId

=88524• Basically the idea is to look at QCD events with one good

muon and look at the ‘fakeable objects’ that can be mistaken as a second muon (background in the analysis)

• It is already possible to start the study in dataRebeca Gonzalez Suarez (08/10/2010) 16

First Results with 4.43 pb-1

• Cleaning the data sample from W, Z and top events (loose VBTF and top selections)

• Using the JetMet, JetMETTau and Jet datasets• Comparing with QCD inclusive Mu 15

Rebeca Gonzalez Suarez (08/10/2010) 17

Still lacking statistics in some PT bins to fully perform itThe QCD selection in data can also be done in a better way (on going)

Next Step in Fakes• But that’s not all: Parallel fake rate study done within

the group for top (see http://indico.cern.ch/conferenceDisplay.py?confId=96963)

• Slightly different approach• We are working in merge the two concepts in one that

can be applied in all the analysis, HWW, WW and top

Rebeca Gonzalez Suarez (08/10/2010) 18

http://indico.cern.ch/getFile.py/access?contribId=2&resId=0&materialId=slides&confId=96963

Yesterday’s talk in top dilepton meeting by

Alicia

Jet Veto/Track Jets/b-tagging• Studies continuously going on by Lara (many presentations)• For 1fb-1 and the three final states together (μμ, eμ and ee)• Applying the WW baseline selection (including softmuon) • Two b-tagging algorithms tested:

– Track Counting (TC)– Secondary Vertex efficiency (SV)

• Summer 10 samples

Rebeca Gonzalez Suarez (08/10/2010) 19

VV VV (TC) VV (SV) ttbar ttbar (TC) ttbar(SV)Events 229.2 221.7 228.3 23.0 13.1 19.6

Reduction 3.0% 0.4% 43.2% 14.8%

Little effect on the signal while greatly reducing the ttbar background

/VVJets_7TeV-madgraph/Summer10-START36_V10-v1/GEN-SIM-RECO/TTbar/Summer10-START36_V9_S09-v1/GEN-SIM-RECO

TrackCounting More efficient/less puritySecondary Vertex More purity/less efficiency

Even if both algorithms are HighEff…

Tagging efficiencies

Track counting High Efficiency algorithm

Based on the requirement of a minimum number of good quality tracks with an impact parameter

significance exceeding a given threshold.

High Eff Simple Secondary Vertex

Reconstructs the B decay vertex using an adaptive vertex finder, and then uses variables related to it,

to calculate its btagging discriminant.

As a function of the btagging discriminant

Btagging efficiency

Mistag rate

Btagging efficiency

Mistag rate

20Rebeca Gonzalez Suarez (08/10/2010)

Tagging efficiencies

Track counting High Efficiency algorithm

High Eff Simple Secondary Vertex algorithm

All jets (PF Jets) are inside |h| < 2.5

As a function of the jet ET

21Rebeca Gonzalez Suarez (08/10/2010)

b-tagging

PF Jets ET VV (TC) VV (SSV) Ttbar(TC) Ttbar (SSV)

0 GeV 221.7 228.3 13.1 19.6

10 GeV 225.5 228.9 13.8 20.4

15 GeV 227.6 229.1 16.4 20.4

20 GeV 228.8 229.2 19.8 21.9

Cut on the ET of the jets used as input for the btagging (after CJV)

Results without b-tagging (including softmuon cut) assuming 1 fb-1

VV 229.2TTbar 23.0 Applying b-tagging

/VVJets_7TeV-madgraph/Summer10-START36_V10-v1/GEN-SIM-RECO/TTbar/Summer10-START36_V9_S09-v1/GEN-SIM-RECO

22Rebeca Gonzalez Suarez (08/10/2010)

HWW Multivariate Analysis (BDT)• We keep as up to date as possible the multivariate analysis for HWW and

WW• We are starting to check the behavior of the data using our latest Training• Still need more statistics to fully prepare a dedicated training for 7 TeV ->

Very early preliminary studies with data

Rebeca Gonzalez Suarez (08/10/2010) 23

tt Z

Example of the Higgs trainings at 7 TeV against WW, tt and Z+jets with data with 3.1pb-1 (not yet optimized)

WW

Summary• Work ongoing in most of the main tasks of the WW and

HWW analysis:

• Synchronized and in-tune with the HWW and WW working groups

• Trigger Validation done in every new release• Effort focused in Tag and Probe, Fake rates and top

background estimation (CJV, Track jets and b-tagging)• Cut-based Analysis for WW and HWW is ready for the data• Continuous work in the Multivariate Analysis (BDT) • Also a Particle Flow study based in Particle Flow Muons, Met

and Jet is going on (coming soon)

Rebeca Gonzalez Suarez (08/10/2010) 24

Backup

b-tagging (TCHighEfficiency)

trackJets

PF Jets

JPT caloJets

26Rebeca Gonzalez Suarez (08/10/2010)

b-tagging (HighEffSimpleSecondaryVertex)

trackJets

PF Jets

JPT caloJets27Rebeca Gonzalez Suarez (08/10/2010)