1. Status of AIF analysis
Daisuke Kaneko

2. Reminder 1 Decided issues
BG PDF : Contains “true AIF” and “accidental AIF”
　→　Use trigger 0 data directory
Signal, RD PDF : Only “accidental AIF”
　→　Simulate accidental by shuffling γ and e+ combination.
PDF
value
entry
comment
Projection
3×1D
Binning
▲Cannot treat correlation between AIF observables
3D Binning
1×3D
▲Much statistics needed for multi dimension
3D Fit
Fitting
▲It is difficult to model distribution is whole analysis area
MVA
1×1D
● Correlation can be considered
● Less statistics needed because 1D

3. Reminder 2 From recent collab. meeting
The shape of PDF for Signal & RMD agrees better with MEG trigger e+ data than random trigger
But Δφ has un-negligible discrepancy
Some AIF are found very close to main e+ track
Probably this is ghost of main e+
ΔθAIF
ΔφAIF
[deg]
AccBG
Sig(trig00)
Sig(trig22)
Sig(trig31)

4. Remaining issues How to make Sig+RMD PDF
Why Δφ distribution still have difference
How to set “No-AIF-candidate” ratio
Is AIF finding algorism correct ?
　Why found candidates are so different by year
　Inefficient candidates are found in small R
　etc.

5. Δφ distribution true pair shuffled pair XEC V γ TC φ
↑Events that do not exist in real pair
↑ structure due to select one TIC hit

6. Trigger simulation LXe γ DCHAIF Interconnection VGamma DCHAIF AIF
Finder
AIF
candidate
mix
Trigger table which was made from true γ and e+ pair ↓
Positron event list
before : vector <Int_t>
new : vector [#bar] <Int_t>
Used list is randomly selected according to VGamma and table.
Used e+ event is randomly selected from the list.

7. Result of trigger simulation
Base shape of Sig+RMD PDF became more similar to BG PDF.
Δθ & Δt PDF did not changed by this.

8. How much is No AIF candidate event
In Signal or RMD event, the probability to find AIF candidate
is smaller than that of BG event, because BG event contain real-AIF event.
If e+ of trigger 0 (BG) event is used for Sig & RMD PDF, the ratio to find AIF become higher than it really is.
Red : AccBG
Blue : Sig & RMD
No-AIF-events are stored in exceptional bin
MVA Index

9. Classification of event type
signal
RMD
BG not
by AIF BG
by AIF γ
e+0 e+1 …
no AIF e+ γ
e+0 e+1 …
no AIF e+ γ
e+0 e+1 …
e+AIFa
No AIF candidate
Category 1
Category 3-1 γ
e+0 e+1 …
e+AIFa … γ
e+0 e+1 …
e+AIFa … γ
e+0 e+1 …
e+AIFa e+AIFb … ? ? ?
AIF is found but not real
Category 2
Category 3-2

10. Ways to calculate “no AIF ratio”
Remove most likely candidate e+
from Cat.3
Scale
Cat.1 & 2
signal
RMD
Trig0
/ trigger 1 A2
B3-2 C2 D2
B3-1 B2 A1 C1 D2 B1

11. Check by example
2012 year, 2000 runs
γ : 48MeV & Acceptance
e+ : positron selection
TOTAL
AIF found
No AIF B1
70499
54400
16059
22.7%
calculate “C-1”
B3-1
Only 1 candidate
B3-2
More than 2 candidates
2852
Select Cat.3 (peak)
by small box
54400
381
2417
C-1 = (B1 + B3-1) / (ALL) = 23.3%
calculate “D-1”
D-1 = (B2) / (B1) = 23.7%

12. remove most likely candidate e+
Black 1
Blue 2
Green 3
no AIF region cut
Black 1
Blue 2
Peak area
cut
The 2nd AIF like e+ when the 1st e+ is in peak similar to base shape.

13. Treatment for few event bin
Example of AIF MVA PDF by BDT method.
Basically the P(SIG)/P(BG)
has increasing trend, but statistically fluctuate at end part.
We think to rebin or use variable width histo to avoid strange likelihood value.
Another way
: Cut far remote region, and store it in OverFlow bin.

14. Summary to make Signal AIF PDF
・Use γ and e+ both from _open trigger 0 data
　　　・If the same event is selected, select a e+ again
・Simulate γ-e+ direction matching
　　　・Simulate also θ and t direction ?
　　　　　　・PDFs already match in its base part
・Ratio of “no candidate”
　　　・C-1 or D-1
　　　　　　・Difference should be systematic ?
　　　・Do include category 3-2 e+ data in shuffling ?
　　　　　　・It is already known that, whether
　　　　　　　remove Cat3 doesn’t make no significant
　　　　　　　difference in distribution shape

15. Remaining issues Finalize Reconstruct Methods
　→ Test Reconstruction Process
Decide MVA methods
　→ Calculation MVA index
Prepare Signal & BG PDF
　→ Start fitting
Estimate systematic error in AIF analysis
　→ Start sensitivity calculation

16. Schedule 3 4 5 6 7 Finalize Reconstruct Test Reprocess
Year/Period investigate
MVA selection
Main Reprocess
PDF preparation
Final check about AIF