The Level-1 CSC Trigger Simulation
— Status & Results —
D. Acosta
University of Florida
with major contributions from
S.M. Wang (UF), B. Tannenbaum (UCLA),
T. Cox (UCD), R. Wilkinson (Caltech)
Outline:
• Software Status
• L1 Trigger results:
• Background rates
• Single muon efficiency
CSC Software Status
• Full C++ description for ORCA written from scratch
in the last 6 months
– Muon package:
• Detector geometry
• Hit unpacking
• Digitization
• Persistency
– Trigger/L1CSCTrigger package:
• Trigger primitive formation
• Regional track-finder
(Cox, Wilkinson)
(Wilkinson)
(Tannenbaum)
(Acosta, Wang)
• Available in head version, tested with ORCA3
• Each subpackage tested independently, but
full system integration tests still ongoing
• No OO track reconstruction for CSC system yet
– Cox and Wilkinson will start this in December
• Preliminary physics results on the Level-1 trigger
performance only are derived from a combination of
standalone programs
D. Acosta, University of Florida
HLT Meeting, November 4, 1999
2
CSC Trigger Primitives in ORCA
• Have entire trigger path coded:
– Anode & Cathode LCT Processor (B. Tannenbaum)
• Anode uses LCT99 logic
• Cathode uses LCT99 logic + bend + Hi/Low pT
– Motherboard (BHT & N. Wisniewski)
• Associates best ALCT with best CLCT
– Portcard (BHT & N. Wisniewski)
• Sorts by ALCT quality * CLCT quality
– Sector Receiver (BHT & T. Truong)
• Uses LUT to determine φ & η from strip & wire
group number.
•
•
•
•
Code is fast
Can read from .fz files
Can read from database
Must still include:
– Pattern based CLCT finding
– RPC information for ghost-busting at motherboard
• Must still compare CMSIM and ORCA resolution
D. Acosta, University of Florida
HLT Meeting, November 4, 1999
3
The CSC Track-Finder in ORCA
• C++ description written by Acosta
• Object design and algorithms follow hardware:
– 12 Sector Processors (6 per endcap) instantiated
– Each Sector Processor contains
• 5 Extrapolation Units
– Link track stubs from 2 stations
• 2 Track Assembler Units
– Form tracks from extrapolations
• 1 Final Selection Unit
– Select best distinct tracks
• 1 Assignment unit
– Assigns PT, φ, and η using a
3-station sagitta measurement
– Output is the three highest rank tracks
– 1 Muon Sorter collects all tracks and selects the four
highest rank (to be collected by the Global Level-1
Muon Trigger)
• DT / CSC overlap region is presently not treated
• Software debugged by making detailed
comparisons with a Fortran simulation (Wang)
D. Acosta, University of Florida
HLT Meeting, November 4, 1999
4
Pt-AssignTF-C++
Comparison of PT
30
25
20
15
10
5
0
0
5
10
15
20
25
30
Entries
Pt-AssignTF-Fortran
10 4
10
3
10 2
10
1
-15
-10
-5
0
5
10
15
Pt-AssignTF-C++ - Pt-AssignTF-Fortran
Difference due to slightly different Track Assembly
procedures for multiple trigger primitives in one station
D. Acosta, University of Florida
HLT Meeting, November 4, 1999
5
L1 CSC Trigger Results
• CSC software for ORCA is not fully validated yet
– This is being addressed now
• C++ Track-Finder is shown to be equivalent to Fortran
version
• Therefore, use trigger primitives from CMSIM and a
standalone Track-Finder to extract background rates
and single muon efficiencies
• Limitations:
– Does not test system in ORCA
– Trigger primitive simulation in CMSIM is naïve (but so is
the one in ORCA presently)
– Results will be “conservative”
• Florida is producing large MC samples for Muon HLT
studies, so switch back on digitization for some
samples.
– Samples generated using same parameters as for HLT:
Pythia and CMSIM116
– Use unweighted Pythia Min Bias events
D. Acosta, University of Florida
HLT Meeting, November 4, 1999
6
Efficiency
Single Muon Trigger Efficiency
Turn-on Curves
1
0.8
0.6
0.4
Pt cut = 10 GeV/c
Pt cut = 20 GeV/c
Pt cut = 30 GeV/c
Pt cut = 40 GeV/c
Pt cut = 50 GeV/c
0.2
1.2<η<2.4
0
0
20
40
60
80
100
Pt (GeV)
Includes geometrical acceptance
D. Acosta, University of Florida
HLT Meeting, November 4, 1999
7
L1 CSC Trigger Rate
(per unit rapidity)
760K unweighted Pythia Min Bias events, Pthard = 0,
with pile-up, put through the Track-Finder simulation
Rate is for 1034 luminosity assuming σ = 55 mb
Rate dN/dηdt (kHz)
µ Rate (Min Bias sample 14 collisions in 1 BX)
Single-µ 3 Stn Pt (|η| > 1.2)
Di-µ 3 Stn Pt (|η| > 1.2)
10 2
10
1
10
10
-1
-2
34
-2 -1
L = 10 cm s
10
-3
1
10
10
2
Ptmin (GeV)
Target rate of 1 kHz for single muons is achieved with 3station sagitta measurement for a threshold of ~15 GeV
D. Acosta, University of Florida
HLT Meeting, November 4, 1999
8