1. Pi0 Simulation for BigCal
Jixie Zhang
June 10, 2015

2. What Is New? https://github.com/jixie/sane_geant3_mc
1. In previous analysis, the weighting of event from various targets (H,He,N,Al) were not considered. The weighting and luminosity calculation were therefore wrong.
2. Total new analysis code.
3. In this analysis, new weighting method is applied.
4. Define pi0 signal as any single that pass electron cut which include Chrencov window cut. Therefore what I show in this talk is background from pi0, not just the positron.

3. Definition of Electron Cut
In the geant3 simulated ntuple, an electron is defined as the following:
A) cer_npe > 60 && cer_npe < 110
B) E_m > 0.5
cer_npe is number of photon electron
E_m is the energy deposited in the BigCal

4. About Thrown Events

5. Number of Atoms in The Target Nose
Material Z
Thickness
(cm)
Density (g/cm^3)
Moll-Mass (g/moll)
Number of Atoms
Al end caps 14
x 2
2.7
26.982 H 1
1.8
NH3=0.817
NH3=
x 3 N 7
LHe 2
0.145
4.003
A) 60% packing fraction,
B) target cell length is 3 cm,
C) the liquid helium thickness outside the cell is 0.5 cm on both ends.
This table shows the relative relation among materials in the target cell. If normalized to N14, the result is:
H : He : N : Al = 3 : : 1 :

6. How to Do The Normalization
1) Fill four 3-D histograms of E:CosTh:phi with cross section of H, He, N and Al.
2) Sum these four 3-D histograms, weighted by the number of atoms in the target. Integrate the result 3-D histogram to get total cross section, XS
3) Count number of thrown events in the simulated ntuple, N, each thrown event is weighted by the number of atoms in the target.
4) Charge is proportional to N/XS
5) The yield from BigCal after all cuts will be scaled by Charge .
electron: threw 15M events,
TotalXS= N_Throw= e+07 N_Detected=1.2441e+07 fScale=
pi0: threw 15M events,
TotalXS= N_Throw= e+07 N_Detected= e+07 fScale=

7. How to Do The Normalization
1) Fill four 3-D histograms of E:CosTh:phi with cross section of H, He, N and Al.
2) Sum these four 3-D histograms, weighted by the number of atoms in the target. Integrate the result 3-D histogram to get total cross section, XS
3) Count number of thrown events in the simulated ntuple, N, each thrown event is weighted by the number of atoms in the target.
4) Charge is proportional to N/XS
5) The yield from BigCal after all cuts will be scaled by Charge .

8. Definition of Electron
In the geant3 simulated ntuple, an electron is defined as the following:
A) cer_npe > 60 && cer_npe < 110
B) E_m > 0.5
cer_npe is number of photon electron
E_m is the energy deposited in the BigCal

9. BigCal RCS: 24 rows x 30 (columns) Y=0 at geant3 code
Protvino: 32 rows x 32 (columns)
different colors indicating the groupings of the trigger channels

10. Binned by groups of blocks
Coded by 2-digit row index and
2-digit column index. i.e. This is 0103
0300
0200
Y=0 at geant3 code
0100
0000
Protvino: 32 rows x 32 (columns)
Grouped by: 8(rows) x 8 (columns)
RCS: 24 rows x 30 (columns)
Grouped by: 6(rows) x 6 (columns)

11. Example
electron

12. PROT Yield for Electron

13. PROT Yield for Pi0

14. RCS Yield for Electron

15. RCS Yield for Pi0

16. PROT Yield Ratio: Pi0 to Electron

17. RCS Yield Ratio: Pi0 to Electron