Conveners Oct G. Bernardi LPNHE - Paris Why do we need Jet-id ? Because there are noise/fake jets What are the Noise/Fake jets ? 1)Noise jets (partly cured by on-line/off-line Data quality corrections) 2)Fake jets are overcalibrated “jets” (either by picking up noise, or in difficult regions like ICR) What are the handles we have ? Precision readout  estimators like EMF, F90 L1 information  allows confirmation (in p14) Tracking  also better in p14 CPS  in p14.05 T42 (as a byproduct)  in d0correct Jet-id / Fake Jets / T42 G. Bernardi for CALGO (thanks to the Top group)

Conveners Oct G. Bernardi LPNHE - Paris Jet-ID Definitions JID: electron removal, JID-f90: JID and ( if f90 < 0.5 or CHF < 0.15 ) L1: JID and ((CC or EC) and L1SET/pT >0.2 or ICD and L1SET/pT >0.1) Track: JID and Sum tracks in 0.5-cone pT / jet pT > 0.05 L1/Track: L1 in CC and EC, Track in ICD L1+Track: L1/Track + Track in CC Perfect jets: L1+Track ( 1) Bad jets : no L1, no Track, JID (-1) Ugly jets: no L1, no Track, JID (-2) Rest: which includes “good” jets (JID-f90) ( 0)

Conveners Oct G. Bernardi LPNHE - Paris Number of bad/good Jets in 50k dijet sample all erem hotf emf> emf< n90 JID f90 L1 L1&T L1/T or L1t Track coml comt dijet: dijet_GRL: djT42GRL: dijet: dijet_GRL: diT42GRL: dijet: dijet_GRL: djT42GRL: black: bad jets from high jet multiplicity green: bad third jet in dijet event blue: good dijet events GRL = good run list applied Bad Jets Good Jets

Conveners Oct G. Bernardi LPNHE - Paris all erem hotf emf> emf< n90 JID f90 L1 L1&T L1/T or L1t Track coml comt black: bad jets from high jet multiplicity green: bad third jet in dijet event blue: good dijet events dijet: dijet_GRL: djT42GRL: dijet: dijet_GRL: diT42GRL: dijet: dijet_GRL: djT42GRL: Bad Jets good Jets Efficiencies for bad/good Jets in 50k dijet sample

Conveners Oct G. Bernardi LPNHE - Paris Conclusions on jet-id / fake&noise jets Some properties of the noise jets: " low pT, sit mainly in the ICD and CH " fake high met, large HT and high jet Multiplicity -> the noise is found where we look for interesting physics In p13 LP03 sample only 45 highest ET towers: -> much lower efficiency to find L1 confirmed jets! T42: 50% reduction of bad jets  Use T42 and Use L1 confirmation for Jet-id. Use Tracks to monitor jet-id efficiencies But….

Conveners Oct G. Bernardi LPNHE - Paris “tmb-fixed” W sample P13 P13 with TMB fix and T42 Em-id: Em Fraction > 0.90 Isolation < 0.15 Em HM8 < 20 |  | < 1.1, In Fiducial vol. p T e > 20 GeV ME T > 25 GeV Standard Jets Criteria: Em Fraction < 0.95 HOTF < 10 f90 < 0.5 or CHf<0.15 |  | < 2.5 P T > 15 GeV (left: loose elec.sel. right: tight elec. sel.)

Conveners Oct G. Bernardi LPNHE - Paris Missing E T, W Transverse Mass P13 P13 with TMB fix and T42

Conveners Oct G. Bernardi LPNHE - Paris Eta of Leading Jet P13 (left: loose elec.sel. right: tight elec. sel.) huge change in the distribution. Coming from the change of ICD Cal_Weight. P13 with TMB fix and T42

Conveners Oct G. Bernardi LPNHE - Paris Reducing influence of Noise: T42 T42: reject ALL isolated cells below 4 sigmas (and ALL negative energy cells) Select high signal cells (4 sigma) Keep their significant neighbours (2 sigma  Thresholds 2  is 2.5  at the moment  T42.5 Full description is available in DØNotes 4124, 4146 Available in D0Reco in shadow mode Not running yet: We wants to have first a tmbfix w/o T42

Conveners Oct G. Bernardi LPNHE - Paris T42 on high energy electrons Estimators for EM candidates in data, when pT>13 GeV OK !

Conveners Oct G. Bernardi LPNHE - Paris T42 on Missing and Scalar E T WZ skim, p13.06, W  e nu selection (E T > 20 GeV, MET > 25 GeV) Compared to Pythia MC No T42 After T42

Conveners Oct G. Bernardi LPNHE - Paris Run Selection with T42 Define the average shift: MET-xy = sqrt [ ( ) 2 +( ) 2 ] RMS-xy = sqrt [ ( RMS-x ) 2 + ( RMS-y ) 2 ] To declare a RUN “GOOD”: 1) Require MET-xy < 6 GeV in all files of a run, and MET-xy < 4 GeV in average 2) Require RMS-xy < 18 GeV in all files of a run and RMS-xy < 16 GeV in average 3) Require scalar E T > 70 GeV in all files of a run and scalar E T > 80 GeV Compare Run selection with and without T42 on 55 pb -1 of p14.03 data

Conveners Oct G. Bernardi LPNHE - Paris Met-xy Shift P Met-xy Shift With T42 Scalar E T P Scalar E T With T42 T42 is “cleaner”

Conveners Oct G. Bernardi LPNHE - Paris P14.03 Jul-Aug 2003 one entry / good “file” (about 20 lumi blocks) Same p14.03 files but processed with T42 xy-shift in Missing E T, xy-rms

Conveners Oct G. Bernardi LPNHE - Paris P14.03 Jul-Aug 2003 one entry / good “file” (about 20 lumi blocks) Same p14.03 files but processed with T42 Scalar and Missing E T (setb,metb)

Conveners Oct G. Bernardi LPNHE - Paris Summary We are progressing ! The potential of p14 is large after all the fixes. Finalize the jet-id  JES can start Watch ICD behavior Use T42(.5) (prepare T42 for restart)