Jean-Roch Vlimant LPNHE november 6, 2002 Comparison of EM-objects between 1.5 and 2.5 pedestal cut. Emid Meeting Jean-Roch Vlimant LPNHE november 6, 2002

Analysis code from Robert & Marumi p10.15 results for Z and W Comparison for run 162594 of Emid objects, Z and W distributions.

p10.15 analysis From Robert & Marumi W and Z stream files Using their analysis framework Using EMid cuts pT>25 GeV EMfrac>0.9 isolation<0.15 Hmatrix<20 W cut ET > 20 Gev

Z peak

W transverse mass

p11 data Run 162594 taken 1.5 online Cuts p11 reconstruction recoA_reco_all_0000162594_0**.raw_p11.11.00.root 2.5 (~2.1) offline cut + p11 reconstruction recoA_reco_all_0000162594_0**.raw_s11.11.00-1.5.root MISSING/ZOMBIE: 02,10,16,20,22,36,38,40,41,48,50,55,73,86,87,90 Cuts Candidates : |id|=11,10 Good candidates : EMfrac>0.9 isolation<0.15 Hmatrix<50 Electrons : |id|= 11 Z : pT>25 GeV ntrack=0,1,2 W : ET>20 GeV

Effect on candidates 2.51.5 : loosing 47% of candidates (68407 35877) loosing events with multiple candidates.

Effect on good candidates 2. 51 Effect on good candidates 2.51.5 : loosing 25% (32622468) Hm8<20 22% (19051477)

Effect on electrons 2.51.5 : loosing 19% (1010821) same number of events with 2 electrons Hm8<20 17% (462387)

Effect on Emfraction 1.5 widens the distribution, more evts at EMfrac>1 and below 0.9 CUT

Effect on Emfraction 1. 5 evens the distribution, gain below 0 Effect on Emfraction 1.5 evens the distribution, gain below 0.9 responsible for loss of good candidates. CUT

Effect on Emfraction after pT cut at 15 GeV effect is less important below 0.9 added CUT

Effect on isolation Smeering towards high isolation for 1 Effect on isolation Smeering towards high isolation for 1.5 responsible for loss of candidates

Effect on isolation after pT cut at 15 GeV 1 Effect on isolation after pT cut at 15 GeV 1.5 candidates are noisy ( negative isolation) added

Effect on Hmatrix 1.5 increases Hmatrix peaks around 10 and 60 CUT

Effect on Hmatrix after pT cut at 15 GeV Hmatrix cut is no longer different below 50 added

different populations pt versus Hmatrix8 at 2.5 NO pT cut added Low pT uniform in Hmatrix ~60 Hpeak is ~15 pT peak Candidates after both cuts

different populations pt versus Hmatrix8 at 1.5 NO pT cut added Low pT uniform in Hmatrix ~60 Hpeak is ~15 pT peak Candidates after both cut

Changes after global normalization added 2.5 1.5 Peak increases Low pT disapear

Effect on pT 2.51.5 : Loose small pTs

Effect on pT 2.51.5 : Loose small pTs

Effect on the di-em events not enough statistics loss of 5 events from good candaidates

Effect on W transverse mass Add event from good candidates before kinematical edge due to ET increasing ~20

Conclusions from 2.5 to 1.5 Loose 50% of candidates to EMid - need better understanding of isolation. Loose 25% of good candidates(10,11) – due to Emfrac and isolation, gain for Hmatrix depends on cut value. Loose 18% electrons(11)- but better identification rates from candidates. Loose few di-em ? - not enough stats to state. Add background to W transverse mass distribution www-d0.fnal.gov/~vlimant/Meeting/CONTRIB/EmidMeeting1.ppt www-d0.fnal.gov/~vlimant/Wps/1.5-2.5sigma-study/nostream/*.ps www-d0.fnal.gov/~vlimant/Wps/1.5-2.5sigma-study/*.ps