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EMID Certification Status

EMID Certification Status. EM selection Description Data-MC comparison Background Efficiencies EM reconstruction Geometrical corrections EM-scale corrections Electronic calibration Energy resolution Some preliminary physics studies Z mass Low energy e + e - resonances.

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EMID Certification Status

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  1. EMID Certification Status • EM selection • Description • Data-MC comparison • Background • Efficiencies • EM reconstruction • Geometrical corrections • EM-scale corrections • Electronic calibration • Energy resolution • Some preliminary physics studies • Z mass • Low energy e+e- resonances Sabine Crépé-Renaudin ISN Grenoble For the EMID group Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  2. Documentation • Certification documentation available on the EMID web page : • www-d0.fnal.gov/phys_id/emid/d0_private/ • certification/welcome.html • Results presented here are based on version 1.2 • Corrections are available in D0 em_util package Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  3. Selection : description • Emreco > p10.08.00, CellNN and Scone algorithm • Abs(id)==10 || abs(id)==11 • 0.95 < EM fraction < 1.05 • -0.05 < isolation < 0.1 • HMx9* < 100 (depends on purity/efficiency needed) • HMx9 = 8x8 matrix without CPS energy (Michel Jaffré) • = available from p10.11 • Note : will be called HMx8 for version > p10.14.00 • Note : Possibility to compute this new Hmatrix for p10.08 to p10.10 version (thanks to Scott Snyder) High pT and isolated electrons Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  4. Data-MC comparison : PT > 20 GeV • Data = EM_HI trigger, EM objects of pT> 20 • pre-shutdown data • MC = QCD plate MC Marc Hohlfeld Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  5. Data-MC comparison : e from Z • Data = di-EM sample around Z mass • MC = Zee plate MC Sergey Burdin Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  6. Background studies : single EM rate • Data = pre-shutdown data, EM_HI trigger, 0.5 pb-1, • pT > 20 GeV, emfrac > 0.95 • MC = QCD MC Marc Hohlfeld • Note : MC has been rescaled (x2) Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  7. Fake rate measurement • Post-shutdown data, Rate vs pT • Jet triggers, 2nd unbias jet, Standard EM selection Shaohua Fu • CC EC • Blue = HMx9 < 100 • Red = HMx9 < 50 • Integrated from pTmin to 200 GeV CC EC • Rate=0.6%+/-0.1% Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  8. Efficiencies measurement : L1 Sarosh N. Fatakia / Ulrich Heintz • Post shutdown data (~240 k events) • Compute turn-on curves for single EM trigger wrt a trigger with lower threshold (max ET trigger tower used) • Translate the curves to efficiencies for EM object (matching ET tower with): EM frac > 0.95, isolation < 0.1, HM9 < 50 • Needs to remove hot cells carefully Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  9. Efficiencies measurement : L3 Ia Iashvili • Last runs before shutdown • Use L3 mark and pass info • Select good EM objects : EM frac > 0.9, isolation < 0.2, HM41 < 200, |h| < 0.8 • EM_LOW rejection = 15 • EM_HIGH rejection = 5.5 (rejection comes mostly from differences in energy scale between L1 and precision readouts) Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  10. Efficiencies measurement : offline Leo Chan • Offline efficiency = • Preselection efficiency (acceptance) • ID efficiency • Preselection efficiency measured by MC (p10.06.00) • Indeed good data-MC agreement for eta distribution (see Sergey plot below) Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  11. Efficiencies measurement : offline • ID efficiencies : • Select di-EM objects • Required one is good quality EM-object, if the Mee reconstructed is in Z mass window assume the second is good also. Apply ID cut to this second object. Compute efficiency after bgd subtraction • Efficiency = 0.99 +- 0.53 for standard cuts in CC • Require SMT track matching for one EM object : allow to reduce significantly the background • Efficiency = HMx9 < 100:0.94±0.06±0.05 HMx9 < 50 :0.94±0.06±0.05 HMx9 < 25: 0.82±0.09±0.05 Leo Chan Yuri Gershtein Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  12. Reconstruction • Aim : improve electron reconstruction and compute EM-scale • Geometrical correction (from MC) : • Cuts for phi cracks • Correct for energy variation with h due mainly to different amount of material present in front of the calorimeter seen by electron at different physical eta • EM-scale (data / MC comparison) • Rescale data electron energy to obtain right Z mass • All correction functions available in em_util package Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  13. Geometrical corrections Sabine Crépé-Renaudin • Obtained on single e- from MC (p10.08.00) • Available for both CellNN and Scone algorithm in CC • Fit energy variation with eta and then compute this variation as a function of energy (5 to 250 GeV) • Results • E loss vs eta • before • after • Scone • CNN Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  14. EM-scale correction Marie-Claude Cousinou / Alexis Cothenet • Compare data and MC Mee distributions • Pre and post-shutdown data • Standard selection • Apply geometrical correction for CC • Etrue = E (1+ e ) • Fit Mee and findewhich maximize a likelihood Mee=91.5 GeV (89 GeV without corrections) • Results : e = 5.6 % ± 0.7 % (CC) e = 0.95 % ± 2. % (EC z<-150) e = 11.2 % ± 2.5 % (EC z> 150) Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  15. Energy resolution Sabine Crépé-Renaudin Yannick Arnoud • MC • Scone : • s(E)/E=(0.23±0.10)/E  • (0.202±0.006)/E  • (0.004±0.002) • CellNN : • s(E)/E=(0.25±0.10)/E  • (0.202±0.006)/E  • (0.003±0.002) • Data • Fit Zee mass and reproduce it using MC and varying energy resolution parameters a, b and c. • Not enough statistics to get precise result Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  16. Electronic calibration M = 84.7 GeV s = 2.9 GeV M = 89.0GeV s = 2.3 GeV Robert Zitoun • Takes into account : • Cell by cell gain (ADC/DAC) dispersion (5 to 10%) • ADC to GeV non linearity (~300 MeV underestimation per cell) • Improves both Zmass mean and resolution • -> EM-scale correction will need to be recomputed • Di-EM mass, after geometrical corrections • Di-EM mass, after geom. corr.+ elec. calib. Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  17. Results : Z mass • Z mass from standard EM selection and ET > 20 GeV • Pre and post-shutdown data Marie-Claude Cousinou / Alexis Cothenet • Final plot after all corrections Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  18. Low mass resonances • Certification results are used … for physics ! • J/y Oleg Kouznetsov Sergey Burdin • U ??? • Very preliminary !! Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

  19. Conclusion • Stable results for Moriond analysis • Updates with post-shutdown data • Results become available for both CellNN and Scone clustering algorithms • Energy corrections will be updated in near future for EC and EM-scale recomputed after R. Zitoun electronic calibration • Use of combined EM/tracks information has started Sabine Crépé-Renaudin D0 General Meeting - February 13, 2002

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