Performance of L1 CSC Trigger
(and strange geometrical effects)
D. Acosta
University of Florida
Eta = 1.6 Region
As reported by Hannes, a large number of high quality
muons reported by L1 CSC trigger originate from PT1 sample
· Contribute ~1 kHz to L1 rate
·
abs(Etac[0]) {Ncsc>0&&Qualc[0]>2&&Ptc[0]>10}
htemp
Nent = 63
Mean = 1.671
RMS = 0.3191
30
25
20
15
10
5
0
1
1.2
PRS/Mu Meeting, July 2, 2002
1.4
1.6
1.8
2
2
2.2
2.4
Darin Acosta
50Kevt
η Distribution of ME Segments
stubeta[0] {nstub>0&&station[0]==1&&Cscid[0]<3}
220
200
htemp
Entries
5937
Mean
76.73
RMS
11.34
ME1/1
180
160
140
120
100
80
60
40
20
0
55
60
65
70
75
80
85
90
95
stubeta[0] {nstub>0&&station[0]==1&&Cscid[0]<6&&Cscid[0]>2}
180
160
ME1/1 and ME 1/2 overlap in η
somewhat: 1.5875–1.6625
100
htemp
Entries
3920
Mean
41.49
RMS
9.393
ME1/2
140
120
100
Creates ambiguity as to which
station to use in PT assignment
80
60
40
20
Also region of detector cracks
PRS/Mu Meeting, July 2, 2002
0
3
25
30
35
40
Darin Acosta
45
50
55
60
η Distribution after Boundary Creation
stubeta[0] {nstub>0&&station[0]==1&&Cscid[0]<3}
htemp
Entries
Mean
RMS
220
undfl
200
5937
76.76
11.3
ME1/1
180
160
140
120
100
80
60
40
20
0
55
60
65
70
75
80
85
90
95
ovflw
stubeta[0] {nstub>0&&station[0]==1&&Cscid[0]>2&&Cscid[0]<6}
220
200
htemp
Entries 3920
ME1/2
180
160
140
120
100
80
Mean
41.42
RMS
9.279
One way to solve ambiguity
is to define the η bins so
that there is no overlap
(even though there is).
Define an upper η bin for
the ME1/2 chamber and a
lower η bin for the ME1/1
chamber (overflow and
underflow bins). The
deviation from the true η is
only 2 bins (0.025 units),
which does not affect the
L1 CSC Track-Finder
efficiency.
60
40
Avoids adding more
memory chips on board
20
0
25
30
35
PRS/Mu Meeting, July 2, 2002
40
45
50
55
4
Darin Acosta
1/PT Resolution
Ptgen/Pt-1
hPtRes
Entries
Mean
RMS
2
χ / ndf
Prob
Constant
Mean
Sigma
22
20
18
16
14
Before:
PT often overestimated
when wrong ME1
chamber was assumed
310
-0.07004
0.3146
54.32 / 37
0.03293
15.63 ± 1.544
-0.0325 ± 0.01664
0.2495 ± 0.01923
(less bending between ME1/2
and ME2, so looks like high pT
if you assume ME1/1 to ME2)
12
10
8
6
4
Ptgen/Pt-1
2
0
-1
-0.5
0
0.5
hPtRes
Nent = 310
Mean = -0.008793
RMS = 0.2597
Chi2 / ndf = 34.3 / 34
Prob = 0.4533
Constant = 19.75 ± 1.637
Mean = -0.01955 ± 0.01439
Sigma = 0.2169 ± 0.01258
25
1
20
15
After:
With clean η boundary,
tail removed and PT
resolution improved
PRS/Mu Meeting, July 2, 2002
10
5
0
-1
5
-0.5
0
Darin Acosta
0.5
1
PT1 Candidates
abs(tracketavalue[0]) {ntrack>0&&trackquality[0]>2&&ptvalue[0]>10}
htemp
Nent = 53
Mean = 1.544
RMS = 0.216
30
Before
25
20
15
10
5
0
1
1.2
1.4
1.6
1.8
abs(tracketavalue[0]) {ntrack>0&&trackquality[0]>2&&ptvalue[0]>10}
2
htemp
Nent = 13
Mean = 1.235
RMS = 0.3243
6
5
4
3
2
1
0
PRS/Mu Meeting, July 2, 2002
1
1.2
1.4
1.6
6
1.8
2
Darin Acosta
After:
low PT muons
removed !
Why ?
A little strange that we see a large impact from this
effect now, because the ambiguity has been there all
along in previous productions
More punch-through in latest production ?
· Larger cracks in geometry ?
·
PRS/Mu Meeting, July 2, 2002
7
Darin Acosta
φ Distribution of η=1.6 Triggers
abs(trackphivalue[0]) {ntrack>0&&trackquality[0]>2&&ptvalue[0]>10&&tracketavalue[0]>=1.6&&tracketavalue[0]<1.7}
16
14
+η Endcap
htemp
Nent = 37
Mean = 3.412
RMS = 1.564
12
·
Why spikes in φ for the η=1.6
triggers before fix? Or why the
asymmetry for that matter ?
·
Not aligned on any sector
boundary
·
About 1/3 are associated with
generated muons with
PT ~ 3 GeV (lower limit of ntuple)
·
About 2/3 of these CSC triggers
have RPC confirmation
10
8
6
4
2
0
0
1
2
3
4
5
6
abs(trackphivalue[0]) {ntrack>0&&trackquality[0]>2&&ptvalue[0]>10&&tracketavalue[0]>-1.7&&tracketavalue[0]<=-1.6}
20
18
+η Endcap
htemp
Nent = 53
Mean = 3.41
RMS = 1.546
16
14
12
10
8
6
4
2
0
0
1
2
3
PRS/Mu Meeting, July 2, 2002
4
5
6
8
Darin Acosta
Distribution of RPC Triggers
abs(Etar[0]) {Nrpc>0&&Ptr[0]>5}
htemp
Entries
467
Mean
1.344
RMS
0.5665
80
Phir[0] {Nrpc>0&&Ptr[0]>5&&(Etar[0])>=1.5&&(Etar[0])<1.7}
htemp
Entries
Mean
RMS
8
68
2.858
1.711
7
70
6
60
5
50
4
40
3
30
2
20
1
10
0
0
0
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
1
2
3
4
5
6
2.2
Phir[0] {Nrpc>0&&Ptr[0]>5&&(Etar[0])<=-1.5&&(Etar[0])>-1.7}
htemp
Entries
Mean
RMS
5
Maximum triggers
for η=1.6
64
2.993
1.831
4
3
2
1
φ Distribution shows spikes
PRS/Mu Meeting, July 2, 2002
0
0
9
1
2
3
Darin Acosta
4
5
6
Correlation with E/Gamma ?
Chris Seez:
·
“We deliberately remove trigger tower 18 (1.479 < eta < 1.566)
from our fiducial region for precision e/gamma work. This
region is strongly shadowed by tracker cables exiting
through the barrel/endcap 'corner' (at eta~=1.479). On the
high side of the corner there are a number of "missing"
crystals - but the location of these small "holes" in the
material is/should be 4-fold symmetric (each quadrant of the
endcap is identical).”
Trig. Tower 18
·
·
Possible correlation, or just
accidental coincidence ?
Barrel-Endcap crack
& tracker cables
η
Anyway, latest CSC simulation removes low pT triggers (but
need to keep an eye on this region if punch-through is large)
PRS/Mu Meeting, July 2, 2002
10
Darin Acosta
Other Changes to L1 CSC Simulation
The addition of the η boundary for the CSC trigger is
implemented in the head of the L1CSCTrigger and
L1CSCTrackFinder packages
·
The ORCA_6_1_1 tagged release is several months old
Many other changes have been made to these
packages to bring them up-to-date with prototypes
currently being built and tested
New anode trigger logic
· New Sector Receiver look-up table scheme
· Additional features in Sector Processor logic
·
But a few more changes to the default settings need to
go in before general release
·
Also to L1DTTrackFinder because of an interface change
PRS/Mu Meeting, July 2, 2002
11
Darin Acosta
CSC Efficiency with Latest Code
Efficiency
Efficiency vs. Pt
hEffPt0
Entries
27
Mean
51.66
RMS
28.03
1
0.8
Basically, as good as it ever
has been
Need to check for fake
di-muon triggers, however
0.6
Efficiency vs. Eta
0.4
1
0.2
0.8
0
0
20
40
60
80
100
Pt (GeV/c)
0.6
0.4
0.2
0
1
PRS/Mu Meeting, July 2, 2002
12
1.2
1.4
1.6
Darin Acosta
1.8
2
2.2
2.4