Conveners

1
Jet-id / Fake Jets / T42
G. Bernardi for CALGO (thanks to the Top group)

• Why do we need Jet-id ?
• Because there are noise/fake jets
• What are the Noise/Fake jets ?
• Noise jets (partly cured by on-line/off-line
  Data quality corrections)
• 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

2
Jet-ID Definitions
JID electron removal, 0.05ltEMFlt0.95, HOTFlt10,
CHFlt0.4, N90gt1 JID-f90 JID and ( if f90 lt
0.5 or CHF lt 0.15 ) L1 JID and
((CC or EC) and L1SET/pT gt0.2 or
ICD and L1SET/pT gt0.1) Track JID and Sum
tracks in 0.5-cone pT / jet pT gt 0.05 L1/Track
L1 in CC and EC, Track in ICD L1Track
L1/Track Track in CC Perfect jets
L1Track (
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)
3
Number of bad/good Jets in 50k dijet sample
all erem hotf emfgt emflt n90 JID f90
L1 L1T L1/T or L1t Track coml
comt 8118 8108 8105 7951 7938 7937 7738 5310
5089 3851 4557 4967 4849 4337 4810 4570 6544
6535 6533 6488 6480 6479 6347 4438 4224 3290 3839
4166 4034 3674 4052 3862 2797 2790 2789 2753
2731 2730 2725 2552 1896 1516 1789 1882 1830 1659
1860 1794 231 230 229 219 217 217
184 117 125 93 113 124 121 109
121 117 188 187 186 177 175 175
151 97 103 79 94 99 100
90 98 95 95 93 93 89
83 83 82 78 54 39 49
53 52 46 53 51 1499 1463
1462 1453 1431 1431 1401 1311 1394 1249 1338 1374
1388 1255 1374 1368 1138 1111 1110 1102 1085
1085 1063 1007 1058 953 1019 1043 1055 958
1043 1040 1296 1239 1239 1233 1222 1222 1212
1184 1203 1086 1166 1198 1202 1093 1197 1196
dijet dijet_GRL djT42GRL
Bad Jets
dijet dijet_GRL diT42GRL
Bad Jets
dijet dijet_GRL djT42GRL
Good Jets
black bad jets from high jet multiplicity green
bad third jet in dijet event
blue good dijet events GRL good run list
applied
4
Efficiencies for bad/good Jets in 50k dijet
sample
all erem hotf emfgt emflt n90 JID f90
L1 L1T L1/T or L1t Track coml comt
100 99.9 99.8 97.9 97.8 97.8 95.3 65.4
62.7 47.4 56.1 61.2 59.7 53.4 59.3 56.3
100 99.9 99.8 99.1 99 99 97 67.8
64.5 50.3 58.7 63.7 61.6 56.1 61.9 59
100 99.7 99.7 98.4 97.6 97.6 97.4 91.2
67.8 54.2 64 67.3 65.4 59.3 66.5
64.1 100 99.6 99.1 94.8 93.9 93.9 79.7
50.6 54.1 40.3 48.9 53.7 52.4 47.2 52.4
50.6 100 99.5 98.9 94.1 93.1 93.1 80.3
51.6 54.8 42 50 52.7 53.2 47.9 52.1
50.5 100 97.9 97.9 93.7 87.4 87.4 86.3
82.1 56.8 41.1 51.6 55.8 54.7 48.4 55.8
53.7 100 97.6 97.5 96.9 95.5 95.5 93.5
87.5 93 83.3 89.3 91.7 92.6 83.7 91.7
91.3 100 97.6 97.5 96.8 95.3 95.3 93.4
88.5 93 83.7 89.5 91.7 92.7 84.2 91.7
91.4 100 95.6 95.6 95.1 94.3 94.3 93.5
91.4 92.8 83.8 90 92.4 92.7 84.3 92.4
92.3
dijet dijet_GRL djT42GRL
Bad Jets
dijet dijet_GRL diT42GRL
Bad Jets
dijet dijet_GRL djT42GRL
good Jets
black bad jets from high jet multiplicity green
bad third jet in dijet event
blue good dijet events
5
Conclusions on jet-id / fakenoise 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
• -gt the noise is found where we look for
  interesting physics
• In p13 LP03 sample only 45 highest ET towers
• -gt 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.

6
tmb-fixed W sample

• Em-id
• Em Fraction gt 0.90
• Isolation lt 0.15
• Em HM8 lt 20
• ? lt 1.1, In Fiducial vol.
• pTe gt 20 GeV
• MET gt 25 GeV

P13

• Standard Jets Criteria
• Em Fraction lt 0.95
• HOTF lt 10
• f90 lt 0.5 or CHflt0.15
• ? lt 2.5
• PT gt 15 GeV

P13 with TMB fix and T42
(left loose elec.sel. right tight elec. sel.)
7
Missing ET , W Transverse Mass
P13
P13 with TMB fix and T42
8
Eta of Leading Jet
P13 (left loose elec.sel. right tight elec.
sel.)
9
Reducing influence of Noise T42T42 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

10
T42 on high energy electrons
Estimators for EM candidates in data, when pTgt13
GeV
OK !
11
T42 on Missing and Scalar ET
WZ skim , p13.06 , W? e nu selection (ET gt 20
GeV, MET gt 25 GeV) Compared to Pythia MC
No T42
After T42
12
Run Selection with T42
Define the average shift MET-xy sqrt
(ltMET-xgt)2 (ltMET-ygt)2
RMS-xy sqrt ( RMS-x )2 ( RMS-y )2 To
declare a RUN GOOD 1) Require
MET-xy lt 6 GeV in all files of a run,
and MET-xy lt 4 GeV
in average 2) Require RMS-xy lt 18
GeV in all files of a run and
RMS-xy lt 16 GeV in average 3) Require
scalar ET gt 70 GeV in all files of a run

and scalar ET gt 80 GeV Compare Run
selection with and without T42 on 55
pb-1 of p14.03 data
13
Met-xy Shift P14.03.02 Met-xy Shift With
T42 Scalar ET P14.03.02 Scalar ET With T42
T42 is cleaner
14
xy-shift in Missing ET, xy-rms
P14.03 Jul-Aug 2003 one entry / good
file (about 20 lumi blocks) Same p14.03
files but processed with T42
15
Scalar and Missing ET (setb,metb)
P14.03 Jul-Aug 2003 one entry / good
file (about 20 lumi blocks) Same p14.03
files but processed with T42
16
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)