1. Drell-Yan Activities for the EWK Group Dimitri Bourilkov University of Florida LPC Di-lepton Meeting, FNAL, March 27, 2008

2. D.BourilkovDrell-Yan Activities for the EWK Group2 Introduction LHC is a high mass di-lepton factory Already with ~100 pb -1 we will be probing regions @ 800+ GeV Be ready to move to high masses immediately after demonstrating the Z peak performance

3. D.BourilkovDrell-Yan Activities for the EWK Group3 Drell-Yan Task Scope: study ee, μμ, e μ above (at startup – also below) the Z peak; ? Measure cross sections and (later) A FB Existing work: Use results from W/Z ee and μμ groups as a baseline; augment with high mass studies from HEEP and TeVmu groups For 1-100 pb -1 extrapolation to higher masses will require MC and (to limited extent due to low event rates) data driven methods. Use ratios where possible. The residual dependence on p T and mass will need simulation inputs Combining ee and μμ (and e μ ) results - vital crosschecks: >cross sections should be ~ equal >same for DY mass spectra (slope), ratios to Z, etc.; as the resolutions for ee and μμ have opposite p T dependence, this will provide an important handle >A FB @ Z, below Z and @ 100-200 GeV should be ~equal

4. D.BourilkovDrell-Yan Activities for the EWK Group4 Efficiencies & Resolutions Efficiencies from data: tag and probe At Z: >trigger efficiencies >offline efficiencies Higher mass: >can not go higher than <~ 250-300 GeV for 100 pb -1 due to limited statistics >backgrounds can be difficult Resolutions from data (p T, mass): Fit Z mass spectrum: advanced Momentum scale calibration High mass: limited statistics, no peak; p T balancing for μ + μ - ?!; leapfrog method for e + e - – how far can we go for lumi < 1fb -1 ?

5. D.BourilkovDrell-Yan Activities for the EWK Group5 Backgrounds MC studies progressing well (CSA07 soups) Data driven methods for jet-jet backgrounds (for ee, μμ ) Electrons: machine background? Muons: cosmics: studies underway machine background: >beam halo >neutrons? need more study

6. Chowder: (/CSA07Muon/CMSSW_1_6_7-CSA07-Tier0-A4-Chowder/AODSIM) tt+jets (up to 4 jets). W+jets (up to 5 jets). Z/gamma*+jets (up to 5 jets) not used in this study because of an upper mass cut. Stew: (/CSA07Muon/CMSSW_1_6_7-CSA07-Tier0-AOD-A01-Stew/AODSIM) BtoJpsi QCD_Pt_0_15 Charmonium Bottomonium Electron_ppEleX Muon_ppMuX Gumbo: (/CSA07Muon/CMSSW_1_6_7-CSA07-Tier0-A1-Gumbo/RECO) "Hard" QCD dijets (p T _hat >15 GeV) Minimum bias Gamma+jets WW, WZ, ZZ: /WW_incl/CMSSW_1_6_7-CSA07-1198096665/AODSIM /WZ_incl/CMSSW_1_6_7-CSA07-1198096684/AODSIM /ZZ_incl/CMSSW_1_6_7-CSA07-1198096655/AODSIM Compare results with the Drell-Yan background and Z′ signal. Use CSA07 background samples (https://twiki.cern.ch/twiki/bin/view/CMS/DigiRecoCSA07Signal) Studies of non-Drell-Yan backgrounds 1.Run over all events in these datasets. 2.Use CSA07EventWeightProducer (v06-15-08-03) to get weights for 100 pb −1. 3.Require OR of non-isolated single-muon and dimuon triggers. 4.Require two muons with M μμ > 400 GeV. Mingshui Chen (Beijing), Univ. of Florida

7. Dijet contribution is ~ as big as Drell- Yan in opp.-sign sample, and dominates same-sign. Two large-weight events from μX: b- bbar with p=30 TeV, and c-cbar with very poor χ 2 /dof (no quality cuts applied yet). Dimuon mass spectra w/o isolation cut Opposite sign Same sign Without isolation cut (and p T > 20 GeV cut): M. Chen (Beijing), Univ. of Florida

8. Require Σp T (in a cone of ΔR=0.3) < 10 GeV. QCD background is suppressed by an order of magnitude. Signal (and Drell-Yan) efficiency go down by 1-2%. Events rejected by the cut (as well as same-sign events before the cut) can be used to study QCD background. Isolation cut M. Chen (Beijing), Univ. of Florida Efficiency as a function of a Σp T (in a cone of ΔR=0.3) cutoff: PAS

9. Dijet contribution is very small. Largest non-Drell-Yan background is > 400 GeV, t-tbar (about ¼ of Drell- Yan). > 1 TeV, W+jets. Not enough stat. to conclude on b-bbar and c-cbar. Dimuon mass spectra w/ isolation cut Same sign Apply isolation cut (and p T > 20 GeV cut): M. Chen (Beijing), Univ. of Florida Opposite sign PAS

10. D.BourilkovDrell-Yan Activities for the EWK Group10 Theory / Monte Carlo Many things in common for ee and μμ PDF uncertainties: well advanced QCD corrections: results with FEWZz @ NLO and NNLO results with MC@NLO for NLO QED ISR/FSR: studies progressing well Genuine EWK corrections: theory calculations, no MC generator ?!

11. D.BourilkovDrell-Yan Activities for the EWK Group11 Signal Definition Standard: cross sections calculated in 4; acceptance calculated e.g. by MC Alternative: define signal cross section to cover where we measure e.g. define CMS di-muon cross section with cut on both muons | μ1 |<2.4 and | μ2 |<2.4  Can calculate directly in PYTHIA, HERWIG, FEWZz …  In this approach events with 1 generated muon || > 2.4 are just part of the background  Eliminates the acceptance calculation  Can publish two (sets of) cross sections: in CMS acceptance region and (different) extrapolations to 4 N obs = L..  =  acceptance.  trigger.  offline-reco

12. D.BourilkovDrell-Yan Activities for the EWK Group12 QCD Corrections – K Functions For a scale 1 * relatively weak mass dependence of the K factors both @ NLO & NNLO NNLO K factors vary by ~ 6 % only from Z to high mass

13. D.BourilkovDrell-Yan Activities for the EWK Group13 Drell-Yan Event Rates and Normalization Mass [GeV]  TOTAL [pb] Acceptance | 1,2 |<2.4  SEL [pb] Events; Ratio to Z 1 pb -1 [%] Events; Ratio to Z 10 pb -1 [%] Events;Ratio to Z 100pb -1 [%] 70-120 1620 0.430 697 700 - 7000 - 70000 - 120+ 18.8 0.483 9.1 9 33 90 10.5 900 3.3 250+ 1.2 0.595 0.70 0.7 120 7 37.8 70 12.0 500+ 0.099 0.7240.072 - 0.7 120 7 37.8 1000+ 0.0065 0.846 0.0055 - - 0. 6 129 2000+ 0.00024 0.920 0.00022 - - - Rough estimate: no K-functions, no efficiency (ee OR μμ) The statistical errors on a normalization to the Z are shown in the table; the errors from PDF uncertainties are 4-8 % for the 500+ or 1000+ bins. For 10 pb -1 the DY background to new physics is negligible above 500 GeV, for 100 pb -1 above 1000 GeV, for 1000 pb -1 around 2 TeV. Any statistically significant accumulation of events in these areas would signal new physics.

14. D.BourilkovDrell-Yan Activities for the EWK Group14 Normalization to Z Peak ‘Data’ Good agreement in ratios between PYTHIA with different PDFs and FEWZz in LO, NLO & NNLO

15. Drell-Yan Tasks List Task (> need volunteers) e + e - μ + μ - Triggers, datasets and skims : Check that efficiencies are good at low and very-high PT + + Offline reconstruction and resolution a) Use Z mass to calibrate scale b) Obtain resolutions from data c) Port existing code to PAT -- write new code in PAT + + Data driven background estimation methods a) of special importance: machine backgrounds > > QED ISR/FSR studies CommonAdvanced QCD corrections : comparison of MCs CommonAdvanced EWK corrections : investigate if any new MC generators and work with theorists Common > PDF uncertainties CommonAdvanced Fast simulation validation - then use for estimating QCD backgrounds > > Systematic uncertainties W/Z and High mass Notes Analysis of global runs data > >

16. D.BourilkovDrell-Yan Activities for the EWK Group16 Outlook TWIKI page: task list will appear there – please sign in https:// twiki.cern.ch/twiki/bin/view/CMS/TWikiEWKDrellYan https:// twiki.cern.ch/twiki/bin/view/CMS/TWikiEWKDrellYan Hypernews - interested people can subscribe: hn-cms-ewk-drellyan@cern.ch Drell-Yan provides tests of the Standard Model at highest momentum transfers (and soon after start-up will push into unexplored territory) Irreducible background for high mass searches Plenty to do before first collisions – feedback and volunteers most welcome CSA07 samples available Test and verify fast simulation for high energy electrons/muons by comparing to full simulation Contacted groups active in high mass (and Z analyses); received feedback from W/Z, HEEP, TeVmu, LPC di-lepton groups

17. D.BourilkovDrell-Yan Activities for the EWK Group17 Backup Slides

18. D.BourilkovDrell-Yan Activities for the EWK Group18 PDF Uncertainties PYTHIA CTEQ6.1 Mass [GeV] xsec [pb] PDF Uncertainty [%/100] CTEQ6.1 Cross Section Xsec ratio to Z Xsec ratio toZ Uncorrelated Correlated 0040-0060 41.07933 + 0.067 - 0.079 + 0 - 0 + 0 - 0 0060-0080 29.11724 + 0.058 - 0.075 + 0 - 0 + 0 - 0 0080-0100 650.3979 + 0.053 - 0.073 + 0 - 0 + 0 - 0 0100-0120 20.91373 + 0.050 - 0.071 + 0.074 - 0.102 + 0.004 - 0.005 0120-0140 4.166503 + 0.047 - 0.067 + 0.071 - 0.100 + 0.010 - 0.010 0140-0160 1.773516 + 0.045 - 0.066 + 0.070 - 0.098 + 0.014 - 0.015 0160-0180 0.9442186 + 0.043 - 0.063 + 0.069 - 0.097 + 0.019 - 0.019 0180-0200 0.5534378 + 0.041 - 0.061 + 0.068 - 0.096 + 0.022 - 0.023 0200-0300 1.047500 + 0.040 - 0.058 + 0.067 - 0.093 + 0.030 - 0.030 0300-0400 0.2334509 + 0.038 - 0.053 + 0.066 - 0.090 + 0.042 - 0.040 0400-0500 0.7916863E-01 + 0.038 - 0.050 + 0.066 - 0.088 + 0.051 - 0.047 0500-0600 0.3307076E-01 + 0.039 - 0.049 + 0.066 - 0.088 + 0.058 - 0.053 0600-0700 0.1550730E-01 + 0.040 - 0.050 + 0.067 - 0.089 + 0.064 - 0.057 0700-0800 0.7982878E-02 + 0.042 - 0.051 + 0.068 - 0.089 + 0.071 - 0.062 0800-0900 0.4451912E-02 + 0.043 - 0.052 + 0.069 - 0.090 + 0.075 - 0.066 0900-1000 0.2634348E-02 + 0.045 - 0.054 + 0.070 - 0.091 + 0.080 - 0.069 1000-1500 0.4326681E-02 + 0.049 - 0.058 + 0.072 - 0.094 + 0.090 - 0.076 1500-2000 0.6327142E-03 + 0.061 - 0.068 + 0.081 - 0.100 + 0.109 - 0.088 2000-2500 0.1307343E-03 + 0.077 - 0.079 + 0.094 - 0.108 + 0.131 - 0.100 2500-3000 0.3304343E-04 + 0.101 - 0.093 + 0.114 - 0.118 + 0.158 - 0.114 3000-3500 0.9280736E-05 + 0.128 - 0.110 + 0.139 - 0.132 + 0.186 - 0.133 3500-4000 0.2832010E-05 + 0.166 - 0.133 + 0.175 - 0.152 + 0.225 - 0.158 4000-4500 0.9166083E-06 + 0.208 - 0.160 + 0.215 - 0.176 + 0.267 - 0.185 4500-5000 0.3097030E-06 + 0.267 - 0.189 + 0.272 - 0.203 + 0.330 - 0.214 5000-5500 0.1052451E-06 + 0.340 - 0.220 + 0.344 - 0.232 + 0.407 - 0.246 5500-6000 0.3560790E-07 + 0.434 - 0.251 + 0.437 - 0.261 + 0.506 - 0.277

19. D.BourilkovDrell-Yan Activities for the EWK Group19 PDF Uncertainties PYTHIA MRST2006nnlo Mass [GeV] xsec [pb] PDF Uncertainty [%/100] MRST2006nnlo Cross Section Xsec ratio to Z Xsec ratio toZ Uncorrelated Correlated 0040-0060 43.31540 + 0.022 - 0.024 + 0 - 0 + 0 - 0 0060-0080 31.37652 + 0.021 - 0.024 + 0 - 0 + 0 - 0 0080-0100 711.2241 + 0.020 - 0.024 + 0 - 0 + 0 - 0 0100-0120 22.31959 + 0.018 - 0.023 + 0.027 - 0.034 + 0.001 - 0.002 0120-0140 4.445462 + 0.017 - 0.022 + 0.026 - 0.033 + 0.004 - 0.004 0140-0160 1.873783 + 0.015 - 0.022 + 0.025 - 0.032 + 0.006 - 0.006 0160-0180 0.9922243 + 0.014 - 0.021 + 0.025 - 0.032 + 0.007 - 0.007 0180-0200 0.5824341 + 0.013 - 0.020 + 0.024 - 0.031 + 0.008 - 0.009 0200-0300 1.089530 + 0.012 - 0.018 + 0.023 - 0.030 + 0.011 - 0.011 0300-0400 0.2444447 + 0.010 - 0.016 + 0.022 - 0.029 + 0.015 - 0.015 0400-0500 0.8363874E-01 + 0.009 - 0.014 + 0.022 - 0.028 + 0.018 - 0.018 0500-0600 0.3411233E-01 + 0.010 - 0.013 + 0.022 - 0.027 + 0.021 - 0.021 0600-0700 0.1597897E-01 + 0.010 - 0.013 + 0.022 - 0.027 + 0.023 - 0.023 0700-0800 0.8369605E-02 + 0.012 - 0.013 + 0.023 - 0.027 + 0.026 - 0.024 0800-0900 0.4557460E-02 + 0.013 - 0.014 + 0.024 - 0.028 + 0.028 - 0.026 0900-1000 0.2710390E-02 + 0.015 - 0.015 + 0.025 - 0.028 + 0.031 - 0.028 1000-1500 0.4430216E-02 + 0.020 - 0.018 + 0.029 - 0.030 + 0.036 - 0.031 1500-2000 0.6344162E-03 + 0.036 - 0.026 + 0.041 - 0.036 + 0.050 - 0.038 2000-2500 0.1321555E-03 + 0.059 - 0.039 + 0.062 - 0.046 + 0.070 - 0.047 2500-3000 0.3309892E-04 + 0.087 - 0.054 + 0.089 - 0.059 + 0.096 - 0.059 3000-3500 0.9441089E-05 + 0.123 - 0.070 + 0.125 - 0.074 + 0.131 - 0.073 3500-4000 0.2948886E-05 + 0.166 - 0.087 + 0.167 - 0.091 + 0.172 - 0.089 4000-4500 0.9577241E-06 + 0.210 - 0.104 + 0.211 - 0.107 + 0.215 - 0.105 4500-5000 0.3230551E-06 + 0.253 - 0.120 + 0.254 - 0.123 + 0.257 - 0.120 5000-5500 0.1090954E-06 + 0.294 - 0.138 + 0.294 - 0.140 + 0.298 - 0.137 5500-6000 0.3693165E-07 + 0.327 - 0.154 + 0.328 - 0.156 + 0.331 - 0.153