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 862Isolation 749 749 749
ID 694 695 695Conversion rejection 694 695 695
tcMET > 20 561 562 562Minv > 12 558 559 559
| Minv - 91.1876| > 15 417 418 418Projected tcMET > 20 && tcMET > 45 203 204 204
PF Jet Veto (ET > 20 && |h| < 3.0) 136 137 137Soft muon veto 135 136 136
Extra 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 2329Isolation 803 803 1513 1513
ID 629 629 1299 1299Conversion rejection 599 599 1280 1280
tcMET > 20 490 490 1034 1034Minv > 12 490 490 1028 1028
| Minv - 91.1876| > 15 384 384 1028 1028Projected tcMET > 20 && tcMET > 45 171 171 883 883
PF Jet Veto (ET > 20 && |h| < 3.0) 112 112 615 615Soft muon veto 111 111 613 613
Extra 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 592Projected tcMET > 20/35 && tcMET > 45 204 258
PF Jet Veto (ET > 20 && |h| < 3/5) 137 179Soft muon veto 136 178
Extra 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=8
8524• 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 caloJets26Rebeca Gonzalez Suarez (08/10/2010)
b-tagging (HighEffSimpleSecondaryVertex)
trackJets
PF Jets
JPT caloJets27Rebeca Gonzalez Suarez (08/10/2010)
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