1. CLEO-III Trigger Systematic Studies Progress Report – M. Selen
Axial Tracking
Study more or less completed
Work done by Inga Karliner (build on work by Randal Hans)
Bottom line: Efficiency for PT>200 MeV ~ 99.9%
Stereo Tracking
A natural extension of the above
Studies done by Charles & Randal have shown this is also extremely efficient. We will quantify this soon.
Calorimeter
Work proceeding in || with CLEO-c sharing (show some plots).
Studies done by Topher Cawlfield (build on work by Jesse Ernst)
Timing
This was “tuned” when the trigger was commissioned.
Will quantify after calorimeter turn-on study.

2. CLEO-III/c Trigger System Overview
TRCR
Mixer/Shaper
Boards
TILE(8)
ASUM
QVME
TILE (16)
AXTR(16)
AXX(16)
DR3 - TQT
STTR(12)
L1D
G / CAL
DFC
CLEO
Analog
Gates
ctrl.
Mixer/Shaper Crates (24)
TPRO(2)
TCTL
TIM
DM/CTL
TPRO(4)
AXPR
CCGL
SURF
Drift Chamber Crates
Axial tracker
Stereo tracker
Barrel CC
Endcap CC
CC Digital
Level 1 decision
Flow control & Gating
DAQ
CLEO-III/c Trigger System Overview

3. Layer 9 = “key”
Inner Lookup
Outer Lookup
Inner/Outer track correlator

4. Tracking Systematic Study
Approach:
Look at CLEO-III Data-5 through Data-16
Select events that pass EL-track line
(#AX>0)&(#CBmd>0)&(AX+CB time)
Select by L3 classification
Loop over “good” reconstructed tracks (c2/dof<3.5, d0<1.5cm, etc…)
Ignore highest momentum track (assume it caused trigger)
Examine trigger status of all other tracks (did it “pass” or not)
“Hadron”
“Electron”

5. To see if a track “passes” trigger:
Extrapolate fit back to layer 9 to see which of the 112 key wires should be asserted.
See if the track-finding hardware for this wire, or either of its immediate neighbors, reports a correlated track.
A track is called “Isolated” if there are no other tracks within ±5 key wires.
If trigger does not fire, see if its because of:
Missing hits (OK)
Hardware (BAD)
Study as a function of tracks PT and cos(q)

6. PT No Trigger - hardware All Tracks No Trigger -missing hits
“Isolated
Tracks” In
Electron
Events
All Tracks PT
1/PT
1/PT
200 MeV
No Trigger
-missing hits
Total Efficiency
1/PT
1/PT

7. PT No Trigger - hardware All Tracks No Trigger -missing hits
“Isolated
Tracks” In
Hadron
Events PT
1/PT
1/PT
200 MeV
No Trigger
-missing hits
Total Efficiency
1/PT
1/PT

8. PT No Trigger - hardware All Tracks No Trigger -missing hits
“Non-Isolated
Tracks” In
Hadron
Events PT
1/PT
1/PT
200 MeV
No Trigger
-missing hits
Total Efficiency
1/PT
1/PT

9. Cos(q) (PT > 200 MeV) No Trigger - hardware All Tracks No Trigger
“Isolated
Tracks” In
Electron
Events
Cos(q) (PT > 200 MeV)
cos(q)
cos(q)
No Trigger
-missing hits
Total Efficiency
cos(q)
cos(q)

10. Cos(q) (PT > 200 MeV) No Trigger - hardware All Tracks No Trigger
“Isolated
Tracks” In
Hadron
Events
All Tracks
Cos(q) (PT > 200 MeV)
cos(q)
cos(q)
No Trigger
-missing hits
Total Efficiency
cos(q)
cos(q)

11. Cos(q) (PT > 200 MeV) No Trigger - hardware All Tracks No Trigger
“Non-Isolated
Tracks” In
Hadron
Events
All Tracks
Cos(q) (PT > 200 MeV)
cos(q)
cos(q)
No Trigger
-missing hits
Total Efficiency
cos(q)
cos(q)

12. Axial Tracking Summary:
For PT > 200 MeV we lose the following due to missing hits:
1 of 41,500 isolated electron tracks
13 of 10,500 isolated hadron tracks
1 of 4,100 non-isolated hadron tracks
Overall efficiency > 99.9%
We don’t lose any tracks due to “missing hardware”.

13. Stereo Tracking Axial high low Stereo - U Stereo - V 112 48 48 high
Raw key wires
Clustered key wires
Axial matching cells
high
low
48 high
48 low
Stereo - U
Stereo - V

14. Topher’s study of CC “turnon” behavior.8 .6 .4 .2
1.0
Need to study

15. Timing Issues Time Bucket Key Wire #track Ev-time CC time – TR time
LOW
MED
HIGH
CC time – TR time
Timing Issues 10
Key Wire
Time Bucket 20 30 40 50 60 70 80 90
100
110 5 15
#track
Ev-time

16. Summary & Plan Axial Tracking Trigger studies more or less finished
Efficiency >= 99.9% for PT > 200 MeV
Stereo Tracking study is next
Expect similar results
Calorimeter studies also under way
Understand turn-on behavior for each TIXEL
Threshold, Width, Max-efficiency
Also needed for MC
Must include sharing. This is non-trivial.
Timing is an issue that still needs to be addressed
TR relative to CC
Overall efficiency