W+jets and Rjets (W+jets/Z+jets) : Status Report

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W+jets and Rjets (W+jets/Z+jets) : Status Report Evelin Meoni On behalf of the Rjets group: G. Arabidze, C. Chavez Barajas, H. Beauchemin, M. Bona, G. Brandt, B. Brau, N. Calace, S. Chouridou, M. Dunford, G. Fletcher, T. Hayashi, J. Huston, R. King, A. Meade, E. Meoni,N. Meric, M. Mondragon, J. Nielsen, J.B. Sauvan, C. Sawyer, A. Tricoli Ed Board Meeting of 3 rd May 2013 1

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W+jets and Rjets (W+jets/Z+jets) : Status Report. Evelin Meoni On behalf of the Rjets group: G. Arabidze, C. Chavez Barajas, H. Beauchemin, M. Bona, G. Brandt, B. Brau, N. Calace, S. Chouridou, M. Dunford, G. Fletcher, T. Hayashi, J. - PowerPoint PPT Presentation

Transcript of W+jets and Rjets (W+jets/Z+jets) : Status Report

Page 1: W+jets and Rjets (W+jets/Z+jets)  : Status Report

W+jets and Rjets (W+jets/Z+jets) : Status

Report

Evelin Meoni

On behalf of the Rjets group:G. Arabidze, C. Chavez Barajas, H. Beauchemin, M. Bona, G. Brandt, B.

Brau, N. Calace, S. Chouridou, M. Dunford, G. Fletcher, T. Hayashi, J.Huston, R. King, A. Meade, E. Meoni,N. Meric, M. Mondragon, J. Nielsen,

J.B. Sauvan, C. Sawyer, A. Tricoli

Ed Board Meeting of 3rd May 2013

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Outline

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• Brief Reminder of the Analysis Strategy

• The status of the Analysis : - Main updates since the last EdBoard meeting or W/Z presentation - Ongoing activities - To Do List

• The status of the documentation

In red in the following slides, updates implemented or planned andquestions for EdBoard and convenors

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Measurement

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SET OF VARIABLES ORIGINALLY PLANNEDNjets : inclusive , exclusive and the ratio (njet/(njet-1) )Njets for pt_lead > 150 GeV: njet/(njet-1) ( Test scaling differences between W and Z)Jets: pT and y of 1st , 2nd ,3rd and 4th jet for Njets>=1,2,3,4 (Rjets) also 5th ,6th, 7th jet (W+jets)Dijets variables: m12,R12, 12, y12

Complex : HT and ST for Njets>=1,2,3,4 and for Njets==1,2,3,4 (Rjets) 5,6,7 (W+jets)Distributions in VBF phase space (mjj>350 GeV, ||>3): pT and y of the 3rd jet Comparison with LO MCs (Alpgen and Sherpa) and with NLO calculations (BlackHat+Sherpa)

WHAT WE HAVEN’T LOOKED AT YET:

- High jets multiplicity distributions for W+jets paper for Njets>= 5,6,7 (W+jets) To be done soon (need to update the analysis framework, not in place currently, quite trivial if ttbar and QCD data-driven work)

-Test of the Scaling in high pT regime (W, and differences between W and Z) and VBF distributions : in place in the framework, but we didn’t look at the results yet. Eventually skip these variables for time constraints issues (and in Rjets skip also scaling with nominal sel Do you (EdBoard and convernors) agree?

-Eventually skip 4 jets distribution in the Rjets paper if uncertainty larger that Z+jets alone

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Strategy (1/2)

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Measurement at detector level : - Data (2011 stat) and MC (mc11c, pileup reweighting applied, corrected for lepton momentum/energy scale and lep eff SF)- Signal measured as Data – BKGs:

Hadron level:-Correct for detector effect (trigger and reconstruction eff. and resolution) with Bayesian Unfolding (RooUnfold) in the same phase space of the detector level measurement with Alpgen (dressed leptons)

Comparisons of unfolded data with LO MCs+PS (Alpgen and Sherpa) and with NLO calculation (BlackHat+Sherpa) corrected

Parton level:NLO calculation corrected by NP effects (fragmentation and UE) and QED effects (born leveldressed)

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Strategy (2/2)• Measurement done first for electron and muon in as similar as experimentally

possible phase space:

• Combination in the common generic phase space :

Correction of unfolded electron and muon results for space-phase done with Alpgen

• About Combination:

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Electrons (dressed level)Z: pT(e)>25 GeV ||<2.47 (crack excl), 66 < mZ < 116 GeVW: pT(e)>25 GeV ||<2.47 (crack excl), pT(v)>25 GeV, MT > 40 GeVJet : pT> 30 GeV |y|<4.4

Muons (dressed level)Z: pT()>25 GeV ||<2.4, 66 < mZ < 116 GeVW: pT()>25 GeV ||<2.4, pT(v)>25 GeV, MT > 40 GeVJet : pT> 30 GeV |y|<4.4

Combination (dressed level)Z: pT(l)>25 GeV ||<2.5, 66 < mZ < 116 GeVW: pT(l)>25 GeV ||<2.5, pT()>25 GeV, MT > 40 GeV

We’ll publish just thecombination

Chi2 method : measurement of Ratio(e) and Ratio () first Combination of the 2 Ratios

Combination Code and References

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Rjets analysis tool on SVN : PhysicsAnalysis/StandardModelPhys/WZJets/WzratioBased on common W/Z baseline selection: https://twiki.cern.ch/twiki/bin/viewauth/AtlasProtected/WZElectroweakCommonTopics2011

Preselection: -trigger - primary vertex (at least one good vertex with >=3 track ) -MET cleaning and LAr Hole Veto

Lepton selection:

Z selection: 2 OS leptons, 66 GeV< mll<116 GeV

W selection: MET > 25 GeV, mT(W) > 40 GeV

Jets selection:

Event selection

Electrons: Tight ++Author 1or 3, Quality flag (OQ&1446 !=0) pT>25 GeV |n|<2.47 (excluding 1.37-1.52)

Muons:STACO Combined with cleaning cuts(MCP recommendations), pT>25 GeV |n|<2.4

Electrons: 2 OS electrons Muons: 2 OS muons, at least the 1st with d0sign (<3), z0(<10mm), isolation requ. (ptcone20/pt < 0.1)

Electrons: 1 tight++ electron

Muons: 1 muon with d0sign,z0, isolation requ.

Electron Trigger e20_medium(D-I), e22_medium (K), e22vh_medium1 (L-M)

MuonTrigger:mu18_MG (D-I), mu18_MG_medium (J,M)

MET: MET_RefFinal, JES and lepton scale prop with MissingETUtility

Antikt4TopoEM at EM*JES scale pT > 30 GeV, |y| < 4.4 |JVF| > 0.75 ( for jets with |η| < 2.4) ΔR(jet-lepton) > 0.5

News: Z selection updated to perform a better measurement in term of Ratio (symmetry between W and Z helps in cancellation of systematics) - pT(muon/electron) =20 GeV 25 GeV-Same trigger for electron channel in W and Z (already the same in muon ch)-Same electron ID for W and Z : 2 OS medium 2 OS tight++ (already the same in muon ch)

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Experimental Systematics

JES, JER, MET, Muon, Electron:For each experimental source varied signal and bkg estimated with MC

BKGSVaried each bkgs by its uncertainty.MC BKGs uncertainties: 5% W Z, Z , W3-4% single top; 5-7% diboson; 10% ttbar

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CURRENT STATUS of Systematics Treatment:Needed an update of electron systematics (following latest EGamma group recommendations)

CURRENT STATUS of Data-driven BKGs in the Analysis Framework:QCD data-driven estimation and uncertainty in place in detector level and unfolded results : - electron ch: latest results in -muon ch: work/tests on-going, but not an updated estimation available yet used data-driven estimation and sys of early Januaryttbar data-driven not yet: tests on-going both at detector level and unfolding, but still results produced with MC ttbar (needed all the pieces before replace MC)

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Detector level plots: an example

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Example taken by the supporting note

Leading jet pT in the electronChannel

In the main body of the supportingnote just : Njets, pT and rapidityof the leading jet (all the rest in the appendix)

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On-going tests on data-driven ttbar

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ttbar(MC)

ttbar(Data-Driven)

W- muon channel

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Unfolding(1/2)

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Unfolded W and Z in each channel (e,) separately Performed R() and R(e) Comb

Unfolding technique: Bayesian iterative unfolding with RooUnfold:- selected events that pass both reco and truth selection-built resp. matrix and fake correction (to account for reco jets in events not passing truth sele)-fake correction applied as a bin-by-bin external correction before unfolding

Unfolding MC: AlpGenClosure: - Used Sherpa to emulate the data: reco Sherpa events unfolded with Alpgen - Compared Sherpa unfolded with the truth Sherpa Closure close to 1

Unfolding Systematics: Method: Bayesian vs. Bin-by-bin ; Modeling: Unfolding with Alpgen vs. Sherpa Statistical Uncertainty:Toy MCs to fluctuate the matrix (RooUnfold implementation)

PLANNED UPDATES:Statistical Uncertainty: write our implementation properly varying all unfolding inputs (matrix truth and reco distributions , fake)Modeling : Difference between Alpgen and Sherpa seems somehow conservative , this could have an impact in the Ratio measurements (one of the main uncertainties) Planned a rebining of a set of distributions (help against statistical fluctuations) Try to look at Alpgen samples with different parameters (samples available by SUSY group), it could take time Do you (EdBoard and convernors) agree?

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Unfolding (2/2)

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Convergence criterium for N_iterations (FINALISED)-Best number of iteration is the one for which the total unfolding systematics is minimal-Studied convergence value (unfolding uncertainty mediated on the all the bins ofthe measurement) vs number of iteration

Minimum around 1-3 iteration, no large difference of the minimum in this range:Chosen 2 iterations for all variables

W Z RATIO

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Systematics on unfolded results

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For each source varied signal (matrix and fake correction) and bkg estimated with MC (for unfolding unc source moved signal only, for bkg unc source moved bkg only)

Something to be fixed in electron channelWhen full chain applied (loop over all the systematics, varying all components) “funny results” obtained. A lot of investigations on-going:-It is not a problem of the unfolding proc or of systematics implementation-Maybe (tests on-going) histograms overwritten in the loop not proper set of shifted histograms used Current results obtained with a “trick” (no fake correction applied)

W

Z

RATIO

electrons muons

electrons muons

electrons muons

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On-going tests on data-driven ttbar

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W- muon channel

Not fair comparison, but it gives an idea:MC case: just 10% uncertainty in ttbar normalization taken (kept ttbar fixed to the nominalvalue when JES/JER and letpton uncertainties varied) Data-driven case: 2 sources of uncertainties for ttbar (JES, light/heavy flavor jets efficiency), ttbar JES uncertainty components correlated with the other JES terms. Jets efficiency uncertainty evaluated as residual ttbar uncertainty in bkg term

Strong reduction of the uncertainty at large multiplicity , but exercise to be completed (full listof syst, check impact on the Ratio)

ttbar (Data-Driven)ttbar (MC)

Preliminary

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Predictions• NLO pQCD preditions with BlackHat+Sherpa : CT10 PDFs , ren and fact scale at HT/2 (scalar

sum pT of all particles/partons in final state)

• Corrections :

• Nominal correction derived from Alpgen+Herwig (Auet2-cteq6l1 tune )syst estimated with Alpgen+Pythia (Perugia2011C)(UE and hadronization) and Sherpa (QED corrections)

NEWs:-New Z predictions (with pT(lepton)>25GeV) : basically same grid of the previous one , justslightly smaller statistics due to the increasing of pT cut

-An update on the calculation of the systematics for UE and hadronisation: before sum in quadrature of UE and hadronisation effects now compared the 2 sets of samples after both UE+hadr effect

- Work on the sys finalized also for the Ratio, prediction uncertainty band included in the results 14

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Results: an example

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News: - Shown Black+Sherpa uncertainty band - Electron plots with all systematics in (even if still needed fixing of the values, no fake applied) - Rebinning already in place in detector level plots, not applied yet at undolding level

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To do list: summary

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- QDC data-driven: already in place in the skeleton of the analysis , but needed finalization of the work in terms of nominal values and uncertainties, mainly in the muon channel (work on-going but status not advanced)- ttbar data-driven: - Tests on going for W channel to include it in the framework of the analysis, but still not complete (soon missing pieces will come, the implementation will be fast) - Needed estimation for the Z channel (both electron and muon): work not started yet- Unfolding: - Problems systematics in electron channel need to be solved soon main obstacle to proceed with combination and to retrieve final conclusions - Some work needed for systematics (minor things): statistical term and modeling one in the unfolding update of the electron term systematics- Combination: - Code set-up with all the inputs available so far - Needed to be completed with the full list of inputs and tested once the results of the single channels will be validated (mainly in electron channel)

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Status of the documentation

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As agreed just one supporting note for W+jets and Rjets. Currently 315 pages (about 50 pages of text the rest plots and appendices)

- Structure defined since a while, a lot of information there and the most updated plots

- Still not ready for CDS or SM circulation, but mature enough for EdBoard with some advice

What can you read? (in red what you cannot read yet)

1.Introduction (even if it will extended in the next and we will add W+jets part)

2. Data and MC simulation samples3.4. Electron Channel and Muon Channel But don’t look at QDC sessions (both

nominal estimation and syst) and ttbar

systematics (in ele ch ttbar missing, details will be added in the next)

5. Detector Level Systematic Uncertainties6. Corrections to particle level7. Systematics Uncertainties on Unfolded

Results But don’t pay too much attention at

electron plots!Still missing comments on the results

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Status of the documentation

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What can you read?8. Combination of electron and muon channels Don’t read we don’t have results yet.What we will add here: - pulls - final combined plots - unfolded systematics breakdown tables - maybe plots of the acceptance corrections9. BlackHat+SHERPA Theoretical predictions10. Results Eventually just look at muon plots, no text there, for some distributions we need to do some cross-check11 ConclusionsA,B,C,D,E,F Appendix Ok, just collections of plots

Basically , don’t read QDC part (text and plots), electron unfolded results (not final) , combination (missing) But the full analysis strategy and a lot of plots are thereMaybe in the next some minor update in the structure (almost systematics plots of unf results in the appendix, more symmetric description of electron and muon ch)

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BACKUP

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Data and MC samples

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• 2011 Data: - period D-M

- GRL: data11_7TeV.periodAllYear_DetStatus-v36-pro10_CoolRunQuery-00-04-08_WZjets_allchannels.xml

- 4.64 fb-1 for each stream (EGamma and Muon)

- SMWZ D3PDs tag p833

• MC: -mc11c samples

Process Generator

W Alpgen+Jimmy(0p..5p) and Sherpa v1.4

Z Alpgen+Jimmy(0p..5p) and Sherpa v1.4

We Alpgen+Jimmy(0p..5p) and Sherpa v1.4

Zee Alpgen+Jimmy(0p..5p) and Sherpa v1.4

Z Alpgen+Jimmy(0p..5p)

WW,ZZ,WZ Herwig

ttbar Alpgen+Jimmy (0p..5p)

Single top AcerMC

- Normalized to (N)NLO XS: https://svnweb.cern.ch/trac/atlasgrp/ browser/Physics/StandardModel/

Common/Winter2012/mc11c_p833_info.txt

-QCD estimated with data driven-techniques

-top : currently estimated via MC use Data-Driven estimation in the

next

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Technical remarks: tags

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Electrons:egammaAnalysisUtils-00-04-25ElectronEfficiencyCorrection-00-00-13

Muons:TrigMuonEfficiency-00-02-30MuonMomentumCorrections-00-07-00MuonEfficiencyCorrections-02-01-11

JETS: JetUncertainties-00-08-05ApplyJetCalibration-00-03-03ApplyJetResolutionSmearing-00-01-02JetResolution-02-00-02

MET:MissingETUtility-01-00-09

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Converge criteria for unfolding

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Convergence criterium, 3 method under evaluation:

1) 2011 Z+jets paper approach:

2) (close to) 2010 W+jets paper approach:

3) Best iteration is the one for which the unfolding uncertainty on XS results is minimal

Used Sherpa to emulate the data and Alpgen to unfold

Stop iterations when difference on 2 consecutive is smaller of the statistical unc

I meth Z

II meth Z

III meth Z

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On-going tests on ttbar

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ttbar(MC)

ttbar(Data-Driven)

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Previous results

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On-going tests on ttbar

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ttbar (MC) ttbar (Data-Driven)

W- muon channel

Not fair comparison, but it gives an idea:MC case: just 10% uncertainty in ttbar normalization taken (kept ttbar fix to the nominalvalue when JES/JER and letpton uncertainties varied) Data-driven case: 3 sources of uncertainties for ttbar (JES: just the main of the JES component,JER, light/heavy flavor jets efficiency) , ttbar JES and JER unc. correlated with the JES and JERTerms. Jets efficiency uncertainty evaluated as residual ttbar uncertainty in bkg term

Reduction of bkg uncertainty component, but exercise to be repeated

Previous results