JetMet

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From p11 to p13
Missing and Scalar ET distributions Warm Zones,
CH, Fake Jets,
Coherent treatment of Calo for jet/met/e.m.
objects for p13 and beyond
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Overview MET-x , MET-y
Rms(MET-x) 1 entry per file.
Relatively stable ltMET-xgt huge variations /- 5
GeV Same story for MET-y
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Distributions ltMET-xgt, rms
4 stores in October (1828, 30, 32, 34), 1
entry per file Not only the shapes are different,
but the rms is also larger when there is a shaky
behaviour. (also true in Met-y) 4 stores at end
of August (1686, 87, 89, 91)
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Good Run definition
Only Runs with gt 1000 events are
considered. (203 runs to start with) Define the
average shift MET-xy sqrt (ltMET-xgt)2
(ltMET-ygt)2 For a GOOD RUN 1) require MET-xy lt
3 GeV in at least 75 of the root-files of the
run. In addition all the root-files must have
MET-xy lt 5 GeV 2) Require mean scalar ET between
90 and 150 GeV We keep 123 good runs ( 60 of
the total statistics, about 8.5 pb-1) Possibility
to reject on a file by file base, since each file
is lumi-block consistent ? only 20
rejected. Same story for MET-y
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Conclusions on Data quality
Warm zones create problems to the missing ET,
rendering the run selection delicate. Problem is
amplified with the soft 2.5 sigma cut (let
alone the famous 1.5 sigma), so situation
naturally becomes easier with the true 2.5
sigma of p13. To save Lumi, it is possible to
provide in addition to the current Run selection,
a file by file selection (one file one lumi
block in stable conditions). Search if we can
find more solutions to the calorimeter
inhomogeneity response
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Warm Zone Identified
Warm zone present in the data since a long time
(before summer 2002) Visible in all e.m.
layers. Not really visible in had. Layer. Low
energy cells. Effect checked on MET by removing
(opposite in phi)
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Warm Zone Identified
Characteritic of a BLS crate problem fix
attempted. To be checked off-line
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Removing Warm Zone from METx,y
Effect on mean, one entry per run. Before A
fter
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Removing Warm Zone from METx,y
Effect on RMS, one entry per run. Before Af
ter
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Removing Arbitrary Zone
Effect on mean, one entry per run. Removing the
warm zone Removing and arbitrary zone of same
size
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Removing Arbitrary Zone
Effect on mean, one entry per run. Removing the
warm zone Removing and arbitrary zone of same
size
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Removing Coarse Hadronic in MET
Effect on mean MET, one entry per run. With
CH Without
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Removing Coarse Hadronic in METx,y
Effect on mean one entry per run. With
CH Without
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Removing Coarse Hadronic in METx,y
Effect on rms one entry per run. With
CH Without
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Removing Coarse Hadronic in METy
mean METy, one entry per run. With CH Without CH
rms METy, one entry per run. With CH Without CH
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P11 Jet Quality Criteria
Reject cone jets if f-90 gt 0.8
0.5CHF (inefficiency for good jets, 3 to 6
) On a muon trigger
sample reject 40
Good jets Fake jets What happens at R0.7 ?
with kT?
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p11.13.00 Data
Cone R0.5
N2/N1?33?
Cone R0.7
N2/N1?60?
N1
N2
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p13.02.00 Data
Cone R0.5
N1
N2/N1?16?
N2
Cone R0.7
N2/N1?30?
N1
N2
Change of noise thresholds back to 2.5 sigma
sharp seems to help
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Cone R0.5
Current algo
Without CH layers
Without CH layers and neg cells
Cone R0.7
Without CH layers and neg cells
Without CH layers
Current algo
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Effect of Coarse Hadronic Layers and negative
cells
Current status of the algorithms
Jets are constructed with a list of positive
energy towers. These towers are made of
positive and negative energy cells.
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Coherent Treatment for p13
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Proposal for p13
All analyses based on p13 should NOT use the
unclustered energy in the CH (layers 15,16,17)
They should use the cells only when they are in
towers which are part of a jet satisfying the
Jet-Met Criteria
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Technically realized by
Computing an initial missing transverse energy
MET-0 (x,y,z components) using all cells of the
CAL block in layers between 1 and 14 and of
positive energy or negative energies, provided
that they belong to a tower of global positive
energy. Here a tower is constructed as usual with
all layers. Adding to MET-0 the 4-momentum of
each jet satisfying the Jet-Met quality criteria
weighted by its coarse hadronic fraction. In this
way we add only the CH energy of the "good" jets,
since the rest of the energy has already been
included in the inclusive computation and since
we don't want to include the CH energy of "fake"
jets. Correcting the missing transverse energy
according to the usual jet and e.m.-objects
corrections, and for the presence of good muons.