General EWK Meeting Christopher Rogan California Institute of Technology V+jets m/e studies with 21X: Status and plans for Marcella Bona, Emanuele Di Marco, Ran Feldesh, Joseph D. Lykken, Paolo Meridiani, C.R., Chiara Rovelli, Maurizio Pierini, Ilaria Segoni, Maria Spiropulu, Thiago Tomei, Lukas Vanelderen, Marco Zanetti

◉ goal of the analyses: ◎ candle with the Z mass: validate e and m reconstruction ◎ application examples: ◍ MC tuning with the dN/dnjets and dN/dp T (Z)‏ ◍ check and correction of MET ◍ ratios good for start-up: systematics cancel ◉ references for 16X analyses: ◎ CMS notes ◉ Z+jets & W+jets Alpgen Validation: CMS AN-2008/091 ◉ Z(ee)+jets Candle Analysis: CMS AN-2008/092 ◉ Z(mm)+jets Candle Analysis: CMS AN-2008/095 ◉ W(en)/Z(ee)+jets Ratio Analysis: CMS AN-2008/096 ◉ W(mn)/Z(mm)+jets Ratio Analysis: CMS AN-2008/105 ◎ previous EWK talks on 16X analysis: ◉ summary by M.Pierini Nov 11 th 2008 ◉ note release: E. Di Marco, C. Rogan, and I. Segoni: Oct 17 th 2008 ◎ V+jets talks: ◉ e and m analyses: I. Segoni and M.Zanetti: Nov 14 th 2008 ◉ m selection: M. Bona: Nov 28 th 2008

Christopher Rogan - EWK Meeting V+j so far

◉ samples: 2.1.X and Fall09 ◎ signals, other Z/W decays and  tt events: MADGRAPH ◎ QCD: “InclusiveMu15” sample (muon enriched QCD)‏ ◉ general strategy for the analyses ◎ single non isolated muon trigger ◎ muon selection: optimization in the next slides ◎ Z mass window [60, 120] GeV/c 2 ◎ closest-to-the-leading-muon PV selection ◎ jet clustering (calo jets and track jets: SisCone with 0.5)‏ with E/p T and h cuts (30/15 GeV and 3/2.4, respectively)‏ ◎ 2D maximum likelihood fit: Z mass and sin(angle MET, MHT )‏ for Z+jets; transverse mass and sin(angle TS-jet )‏ ◎ floating the shape parameters for low jet multiplicities and fixing for the high multiplicities ◎ sPlots for verify shapes on data

◉ muon selection in 16X ◎ only global muons ◎ p T > 15 GeV/c ◎ vertex variables and isolation variables simultaneous optimization: ◉ vertex variables: Dxy/s(Dxy) and Dz(m-PV)‏ ◉ isolation variables: tracking isolation  i p i T /p m T ECAL isolation  R<0.35 E T ECAL HCAL isolation  R<0.5 E T HCAL ◍ extensive study to select the variables and to establish the optimization procedure: done in 16X and now repeated in 21X production, the PV is displaced in x so we can calculate the distance wrt the PV but the error is calculated wrt (0,0,0)‏ so we started looking at: Dxy better for the electrons that have typically poorer tracking resolution about the same discrimination for muons (wrt the significance)‏ in 21X production, the PV is displaced in x so we can calculate the distance wrt the PV but the error is calculated wrt (0,0,0)‏ so we started looking at: Dxy better for the electrons that have typically poorer tracking resolution about the same discrimination for muons (wrt the significance)‏ Hcal isolation: H0 excluded and zero suppression introduced Hcal isolation: H0 excluded and zero suppression introduced

Christopher Rogan - EWK Meeting Cut variables  i p i T /p m T  R<0.35 E T ECAL  R<0.5 E T HCAL Dz(m-PV)‏ Dxy

Christopher Rogan - VecBos + jets Optimization on the W selection  Optimize the Punzi Significance:  Consider all backgrounds and scan over all cut values simultaneously, with rates normalized to 100 pb -1  Consider only events in ML fit ‘signal region’

Christopher Rogan - VecBos + jets Optimization scans requiring:  R<0.35 E T ECAL  R<0.5 E T HCAL  i p i T /p m T <0.15 <2.25 GeV <2.8 GeV

Christopher Rogan - VecBos + jets Dxy(PV)‏Dz(m-PV)‏ Optimization scans requiring: <0.11 cm<0.005 cm

Christopher Rogan - VecBos + jets Optimized cut values (n.a.)‏ (0.08)‏ (6.0)‏ (1.6)‏ (0.11)‏ Values used Values used Calo jets Track jets

Christopher Rogan - EWK Meeting Optimized cut values Values used Values used Calo jets Track jets

Christopher Rogan - EWK Meeting Changing muon pt cut W selection

Christopher Rogan - EWK Meeting Changing muon pt cut Z selection

Christopher Rogan - EWK Meeting Analysis strategy Common requirements: Single non isolated HLT trigger (HLT_Ele15_LW_L1R) pixel-match GSF electron reconstruction electron identification* electron isolation* electron - PV compatibility calo-jet clustering (SisCone, ΔR=0.5) electron(s) from W(Z) cleaning from calo-jets jet counting W-specific requirements: exactly 1 electron (against Z+j) Z mass veto (decouple W+j dataset from Z+j) MET > 20 GeV (against QCD) m T (W) > 30 GeV (against QCD) Z-specific requirements: ≥2 electrons (against W+j) Z mass range (decouple Z+j dataset from W+j) yields and ratio determination: Maximum Likelihood fit efficiency correction of yields, if needed * for Z, asymmetric id+iso

Christopher Rogan - EWK Meeting why re-iteration with 2.1.X ? electron reconstruction details changed w.r.t. 1.6.X. (i.e. CSA07) tracker material changed some electron identification related to tracker - ECAL match can be changed among others, H/E definition changed pre-shower is excluded HO is excluded and zero-suppression in HCAL has been introduced H/E is affected HCAL isolation is affected PV is displaced in x w.r.t. (0,0,0) In this iteration, possibly no new variables w.r.t. the ones used in CSA07 analysis are used. Various new quantities have been developed and released, will be tested in next round Disclaimer!

Christopher Rogan - EWK Meeting Electron identification We use the set of variables from egamma POG, with selection depending on electron classification (based on f brem ) we compare 2.1.X X and re-optimize selection for golden / showering both barrel and endcap this defines the W electron and the first Z electron (i.e. tight) loose egamma identification on the other (asymmetric ID) tracker-ECAL match ECAL-HCAL match ECAL cluster shapes

Christopher Rogan - EWK Meeting Efficiency of ele - id Cuts optimized simultaneously to maximize W signal significance against QCD QCD e.m. enriched + b,c→electrons used the optimization is driven by W+j. For Z+j, the highest pT electron is identified with the same criteria to allow efficiency cancelation in Wj/Zj the ID of the second is based on the same variables, but looser selection ε(CSA07) ε(Summer08) / /- 0.1-*- s9s25: / /- 0.1-*- deta: / /- 0.1-*- dphiIn: / /- 0.1-*- sigmaEtaEta: / /- 0.1-*- eOverPout: / / *- total eID: / /- 0.2 Single electron efficiency on W+≥0j The optimized cuts egamma loose

Christopher Rogan - EWK Meeting S and B yields (W+j) yields, normalized in 100 pb -1, up to electron definition. large stat error

Christopher Rogan - EWK Meeting S and B yields (Z+j) yields, normalized in 100 pb -1, up to electron definition

Christopher Rogan - EWK Meeting m(e + e - ) lineshapes Cruijff = Gaussian + exp tails for signal, parabola for inclusive bkg ≥1 jet≥2 jet≥3 jet Z+jets (MADGRAPH) tt+jets (MADGRAPH) consistent parameters for signal lineshape as a function of jet multiplicity

Christopher Rogan - EWK Meeting m T (W) lineshapes Cafu = Crystal ball + Gaussian with same mean ≥1 jet ≥2 jet W+jetstt+jetsZ+jetsQCD decreasing importance

Christopher Rogan - EWK Meeting slope correction Yields uncorrectedYields efficiency-corrected W+j Z+j e -Slope =7.5±1.2 e -Slope =6.8±0.5 e -Slope =6.9±1.1 e -Slope =6.8±0.5 W/Z = 1.09±0.20W/Z = 1.01±0.19 ⇒ eff changes the slope, but effect on double ratio is within uncertainty Preliminary

Christopher Rogan - EWK Meeting slope correction Yields uncorrectedYields efficiency-corrected W+j Z+j W/Z = 0.91±0.05 ⇒ eff changes the slope, but effect on double ratio is within uncertainty e -Slope =7.32±0.09e -Slope =6.82±0.08 e -Slope =8.0±0.4e -Slope =7.4±0.3 W/Z = 0.93±0.04 Preliminary

Christopher Rogan - VecBos + jets ◉ for the candle analysis: ◎ we start from the optimization values obtained for the ratio in the W selection we can afford to loosen the cut to increase efficiency ◉ muon p T > 10 GeV/c ◉ vertex variables: Dxy <0.02 cm & Dz(m-PV) <0.15 cm ◉ isolation:  i p i T /p m T <0.30 (on the second leg)‏ Preliminary

Christopher Rogan - EWK Meeting Preliminary ≥1jet Background

Christopher Rogan - VecBos + jets ≥1jet ≥2jet ≥3jet ≥4jet Signal

Christopher Rogan - VecBos + jets ≥1jet ≥2jet ≥3jet ≥4jet Background

Christopher Rogan - VecBos + jets ≥1jet ≥2jet ≥3jet ≥4jet Signal

Christopher Rogan - VecBos + jets ≥1jet ≥2jet ≥3jet ≥4jet Background

Christopher Rogan - VecBos + jets ◉ for the electron candle analysis: we can afford to loosen the cut to increase efficiency ◉ electron p T > 10 GeV/c ◉ loose electron ID on both legs ◉ Best Z candidate choice (highest pt electrons) ◉ vertex variables: Dxy <0.04 cm & Dz(m-PV) <0.12 cm ◉ isolation:  i p i T /p m T <0.15 (on both legs)‏ Preliminary

Christopher Rogan - EWK Meeting ≥1jet ≥2jet ≥1jet ≥2jet Signal

Christopher Rogan - EWK Meeting ≥1jet ≥2jet ≥1jet ≥2jet Background

Christopher Rogan - EWK Meeting EXTRA SLIDES

Christopher Rogan - EWK Meeting Madgraph/Alpgen Production changes  For tt+j  parton pt 20, matched at 30 MADGRAPH – KT MLM matching  x-section 10 TeV, x-section TeV  Parton pt 70, matched at 20 GeV, ALPGEN –MLM (old, IC) Matching  x-sec 450 TeV – if 20 GeV parton pt x-sec 754 TeV,  x-section TeV [15% compared to MAD, MAD>ALPGEN but different scales, PDFs see below]  Scale (m_top)^2 at MADGRAPH  Scale (M_T)^2=sum(m_top^2+P_T^2) ALPGEN  Lower Q^2 pushes the cross section up (MAD>ALPG) (10%)  PDF CTEQ6L NLO and corresponding a_s change in MADGRPAH  PDF CTEQ5L LO ALPGEN  NLO PDF pushes x-section up (MAD>ALPG) (10%)

Christopher Rogan - VecBos + jets Comparison of isolation variables: CSA07 - FALL08

Christopher Rogan - VecBos + jets Comparison of vertex variables: CSA07 - FALL08 significance

Christopher Rogan - VecBos + jets ◉ isolation variables: tracking isolation normalized:  i p i T /p m T ECAL isolation:  R<0.35 E T ECAL HCAL isolation:  R<0.5 E T HCAL tracking isolation: tracks within DR < 0.5 ◈ at least 5 associated hits ◈ | Dz(track-PV)| < 0.1 cm ◈ |Dxy/s(Dxy)| < 5 ◈ 500 MeV/c < p T < 500 GeV/c ECAL isolation: EM calotowers in the 0.35 cone around the m m energy is not subtracted HCAL isolation: hadronic calotowers in the 0.5 cone

Christopher Rogan - VecBos + jets W selection efficiencies Preliminary

Christopher Rogan - VecBos + jets Z selection efficiencies Preliminary

Christopher Rogan - EWK Meeting E seed /P out Major point: track p out estimation depends by the tracker material knowledge barrelendcap

Christopher Rogan - EWK Meeting Δη vtx GSF-track - ECAL supercluster match larger tails for non-showering non-showering endcap bumps for η>0, η<0: tilt changed in the geometry? barrelendcap

Christopher Rogan - EWK Meeting ΔΦ vtx GSF-track - ECAL supercluster match barrelendcap

Christopher Rogan - EWK Meeting H/E CSA07: H/E = sum(H rechits) / supercluster energy in cone ΔR=0.1 no HCAL zero-suppression Summer08: H/E = max (H rechit / basic cluster ), the H rechit is the one above the ECAL basic cluster HCAL zero - suppression barrelendcap

Christopher Rogan - EWK Meeting s 9 /s 25 Cluster shape variable barrelendcap

Christopher Rogan - EWK Meeting σ ηη Cluster shape variable (cluster width) changed thresholds? barrelendcap

Christopher Rogan - VecBos + jets Optimization scan requiring: Dz(m-PV)‏ Dxy(PV)‏  R<0.35 E T ECAL  i p i T /p m T  R<0.5 E T HCAL

Christopher Rogan - VecBos + jets  R<0.35 E T ECAL  i p i T /p m T  R<0.5 E T HCAL Dz(m-PV)‏ Dxy(PV)‏ Optimization scan requiring:

Christopher Rogan - VecBos + jets Optimization scan requiring:  R<0.35 E T ECAL  i p i T /p m T  R<0.5 E T HCAL Dz(m-PV)‏ Dxy(PV)‏

Christopher Rogan - EWK Meeting Optimization  Some comments:  Currently we are not including a sphericity cut or MET cut in the optimization (we will include this once I finish the W MET calibration using the Z candle)  As a result, we are cutting more tightly on these five variables relative to what we will do when including MET or sphericity - I anticipate that the signal efficiency will go up with  Ultimately, we will also do the optimization in the signal region of the ‘angular variable’ which we use in the fit - we can’t do this until we have the W MET calibration.  Hence these are probably not the ‘final’ values, but they demonstrate the procedure/philosophy of the optimization

Christopher Rogan - EWK Meeting what looks different Most of the electron ID variables looks very similar to CSA07. (see backup) larger differences in: H/E, σ ηη H/E: definition changed, was H/E in a cone ΔR=0.1, now is H over- ECALseed /E seed σ ηη : noise threshold for covariance matrix calculation changed (w 0 =4.2 → 4.7): expected larger width H/E barrel σ ηη barrel

Christopher Rogan - EWK Meeting what’s looks different: Δη vtx double peak for golden (i.e. when the super-cluster = 1 basic cluster) in the endcap peak>( )0 true also evaluating Δη=η clus -η genele it is a cluster problem difference 1.6.X X: 2.1.X has not the preshower: the cluster position (depth in crystal) accounts for it with a parameter hypothesis check. In 3.0.X preshower is back the double peak disappears η clus -η genele η Δη vtx (3.0.X)

Christopher Rogan - EWK Meeting electron isolation Comparison of the variables used in the CSA07 notes Traker: sum(p T tracks )/p T ele, with internal cone veto internal cone veto found to be good and robust external cone ΔR=0.4: all similar, chosen the intermediate one ECAL: sum(E T 5x5 crystals -E T super-cluster )/E T super-cluster in a cone ΔR=0.4 electron footprint E T super-cluster not optimal, move to rechits isolation soon HCAL: sum(E T rechits )/E T super-cluster in a cone ΔR=0.4 ECAL rechits removal tracker veto cone See summary from M. Le Bourgeois:

Christopher Rogan - EWK Meeting isolation: distributions trackerECAL HCAL isolation ε(CSA07) ε(Summer08) - *- tracker: / / *- ECAL: / / *- HCAL: / /- 0.2

Christopher Rogan - EWK Meeting vertexing variables Used to suppress events not coming from Primary Vertex (PV): dz = z ele -z PV dxy = distance in transverse plane w.r.t. PV RMS=210μmRMS=66μm

Christopher Rogan - EWK Meeting jet multiplicity dependency (1) efficiency variations in different multiplicities change the slope V+(n-1)j / V+(n)j but mostly cancels out in double ratio W+nj / Z+nj (W ele and 1 st ele of Z have the same selection) Z+jets: no variations at all re-estimate on Fall08 samples with HLT

Christopher Rogan - EWK Meeting jet multiplicity dependency (2) W+jets: 2% drop at each added jet re-estimate on Fall08 samples with HLT

Christopher Rogan - EWK Meeting maximum likelihood fit signal, backgrounds yields extracted on data with extended, maximum likelihood fit for Z+≥1jet also Z lineshape parameters extracted on data Z+jets: 1dim fit: P=PDF(m ee ) W+jets: 1dim fit: P=PDF(m T W ) N i =signal and backgrounds yields Z+jets: i=signal, tt W+jets: i=signal, tt+QCD, Z+jets total number of events entering the fit (i.e. extended likelihood)

Christopher Rogan - VecBos + jets Tracking Isolation  i p i T /p m T comparison wrt the jet bin

Christopher Rogan - VecBos + jets ECAL Isolation  R<0.35 E T ECAL comparison wrt the jet bin

Christopher Rogan - VecBos + jets HCAL Isolation  R<0.5 E T HCAL comparison wrt the jet bin

Christopher Rogan - VecBos + jets vertex variable: Dz(m-PV)‏ comparison wrt the jet bin

Christopher Rogan - VecBos + jets vertex variable: Dxy comparison wrt the jet bin

Christopher Rogan - VecBos + jets W selection results Calo jets Preliminary 16X numbers: CAVEAT different cuts and different energy!

Christopher Rogan - VecBos + jets W selection results Track jets Preliminary

Christopher Rogan - VecBos + jets Z selection results Calo jets Preliminary 16X numbers: CAVEAT different cuts and different energy!

Christopher Rogan - VecBos + jets Z selection results Track jets Preliminary

Christopher Rogan - EWK Meeting W slopes Calo jets

Christopher Rogan - EWK Meeting W slopes Track jets

Christopher Rogan - EWK Meeting Z slopes Calo jets

Christopher Rogan - EWK Meeting Z slopes Track jets

Christopher Rogan - EWK Meeting Calo jets Track jets

Christopher Rogan - EWK Meeting W/Z Ratio