Comparison of EM-objects between 1.5 and 2.5 pedestal

cut.

Emid Meeting

Jean-Roch Vlimant

LPNHE

november 7, 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 cutspT>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

– 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 candidates2.51.5 : loosing 47% of candidates (68407 35877)

loosing events with multiple candidates.

Effect on good candidates2.51.5 : loosing 25% (32622468)

Hm8<20 22% (19051477)

Effect on electrons2.51.5 : loosing 19% (1010821)

same number of events with 2 electronsHm8<20 17% (462387)

Effect on Emfraction1.5 widens the distribution, more evts at EMfrac>1 and

below 0.9

CUT

Effect on Emfraction1.5 evens the distribution, gain below 0.9 responsible

for loss of good candidates.

CUT

Effect on isolationSmeering towards high isolation for 1.5 responsible for

loss of candidates

Effect on Hmatrix1.5 increases Hmatrix peaks around 10 and 60

CUT

Effect on pT2.51.5 : Loose small pTs

Effect on pT2.51.5 : Loose small pTs

Effect on the di-em eventsnot enough statistics

loss of 5 events from good candaidates

Effect on W transverse massAdd 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.pptwww-d0.fnal.gov/~vlimant/Wps/1.5-2.5sigma-study/nostream/*.ps

www-d0.fnal.gov/~vlimant/Wps/1.5-2.5sigma-study/*.ps