Arguments (from trigger point of view)
in favor of an improved RE1/2
Karol Buńkowski,
University of Warsaw
General Muon meeting
6 May 2013
Introduction
• There are no any studies yet how the improved
detector in the RE1/2 can improve the trigger
performance (i.e. decrease the rate without
decreasing the efficiency).
• In this presentation only some argument based
on “deduction”.
General Muon meeting, 6 May 2013
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Karol Buńkowski, UW,
GMT rate vs.  @ pTcut 16 GeV
• In the current muon trigger the highest rate comes from:
•
•
1. High eta region  < 2.1
2. Overlaps region 0.8 <  < 1.2
3. Region of ~1.4 <  < 1.6
The ME4 and RE4 are coming after the LS1 – should help to reduce
the rate in the region 1.2 <  < 1.8 (1.6).
The new Muon Trigger will combine the data from the three muon
detectors in the common Track Finder – hope for the rate reduction
(but no algorithm and no estimations of the rate reduction yet).
General Muon meeting, 6 May 2013
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Karol Buńkowski, UW,
Current RPC system geometry
General Muon meeting, 6 May 2013
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Karol Buńkowski, UW,
Current Muon detector geometry
CMS L1 Trigger Review, 11 October 2011
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Karol Buńkowski, UW,
CSCTF rate  vs. 
@ pTcut 16 GeV


General Muon meeting, 6 May 2013
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Karol Buńkowski, UW,
CSCTF rate vs.  @ pTcut 16 GeV
CSCTF rate vs phi
in 1.2 <  < 1.6

No LTC in the ME1/2
 trigger rate ~8 times higher
 The ME1 is crucial for the pT measurement
The ME1 efficiency for generating of the CLCT is
~98% (MUO-11-001). So ME1/2 inefficiency can be
responsible for the ~16% of the rate increase in this
region (2% × 800%).
General Muon meeting, 6 May 2013
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•
CSC: quality 1-3
|eta|>1.2:
Quantity 3:
any 3 station tracks
Quality 2:
any 2 station tracks with ME1 station
any 2 station tracks at |eta|: 1.5-1.6
Quality 1:
all other tracks including:
- halo muon(2 station tracks)
- single (1 station track)
- any 2 without ME1 station
at |eta|: 1.2-1.5, 1.6-2.1
Karol Buńkowski, UW,
Magnetic field map
General Muon meeting, 6 May 2013
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Karol Buńkowski, UW,
 between the RPC stations
1.36 <  < 1.48
1.36 <  < 1.48
There is almost no bending
between the RE2 and RE3  the
 resolution does not play big
role.
(more important is the multiple
scattering of the low pT muons,
which can also be used as the
discriminations factor)
The bending between
the RE1 and RE2 is not
very big, therefore the 
resolution does play a
role.
 of the positive
and negative
muons overlaps
pTcut 18 GeV
•
Precise measurement of the local
angle in the ME1/2 can probably
improve the pT measurement
significantly and reduce the rate
General Muon meeting, 6 May 2013
•
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pTcut 18 GeV
RPC strip
2/1152 = 0.0055 rad, but clusters
decreases the resolution ~ 2×times
CSC half strip
2/5760 = 0.001 rad
Karol Buńkowski, UW,
Conclusions
• The first muon station is the most important
for the pT measurement, and the trigger rate
reduction (this is true for the entire muon
detector, not only for the endcaps).
– The efficiency and the geometrical coverage
should be close to 100% (as much as possible).
– The spatial resolution of the first station plays a
role.
– The local angle of the track segment in the first
station can probably improve the pT measurement
significantly and reduce the rate.
General Muon meeting, 6 May 2013
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Karol Buńkowski, UW,
Backup
General Muon meeting, 6 May 2013
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Karol Buńkowski, UW,
General Muon meeting, 6 May 2013
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Karol Buńkowski, UW,