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Particles with EPD hit analysis

Updated on Mon, 2018-06-11 07:38. Originally created by rolandp on 2018-06-08 06:45.

I have continued my previous study, which can be found here.
The things I did now: analysing the particles which hit the EPD, concerning many details.
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Summary:
- PID for particles hitting the EPD based on GEANT ID
- There are 169 hits with GEANT ID = 0, which are not listed in the table.
- GEANT ID 35,36,37,38,39,40 are not listed neither, but found them elsewhere.
- Neutrinos have a significant Deposited Energy [keV] in the EPD.
- 0.3% of the particles hitting the EPD have |eta| < 0.1, mostly they are PION 0/+/-.
- There is a big peak in the Deposited Energy around 0.002 keV.
- There are some particles with eta ~ 0  with not too small Pt values.
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(1) Particle Identification
I made a histogram about the particles hitting the EPD:

 
On the x axis, we can see the GEANT ID of the particles, based on this table: https://www.star.bnl.gov/public/comp/simu/gstar/Manual/particle_id.html
It was not enough informative for me, so I made a txt about this histogram as well: http://www.star.bnl.gov/~rolandp/back_scattering/particledata.txt
It's quite strange that there are several GEANT IDs for which THERE IS NOT ANY particle type listed in the table. However, here, I could find the missing IDs, except Geant ID = 0.
As it can be seen from the picture above, and from the txt as well, the most hitting particles were the following:
- 1: gamma
- 2,3: e +-
- 4,5,6: neutrino, muons
- 7,8,9: pions
- 14,15: protons +-
- 13,25: neutrons
- 45,46,47 nucleii

Since there were several neutrinos, nearly 3% of the particles were them, I analysed them further a bit.
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(2) Neutrinos
Pseudo rapidity (eta), Deposited energy, Pt  distribution for neutrinos:
 

For neutrinos, that deposited energy is not too much? What we know is that the probability for neutrinos interacting with matter is low, but what about the deposited energy when they eventually interact? Is this ok/acceptable?
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(3) Pseudo rapidity
Mike asked in my previous study, which particles have eta ~ 0 due to this plot: 



 
Well, I did as he asked, I thought maybe I should investigate a small interval for eta, like -0.1 < eta < 0.1, so I made a 1D histogram for |eta| < 0.1 and a 2D PID for |eta| < 0.1:
 
We can see that there are 2682 particles with that small eta, out of the 872212, so ~0.3% of the particles have an |eta| < 0.1.
As it can be seen, Geant ID 7,8,9 particles (PION 0,+,-) have mostly that small eta value.
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(4) Deposited energy[keV]
I made plots about the particles' hitting the EPD deposited energy:
We can see a big peak around 0.002 keV, which could be seen at the neutrinos as well.
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(5) Eta - Pt, PID - Pt, PID-eta distribution

 

 
We can see that with eta ~ 0 there are some particles with not too small Pt value.
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