rjones30
commented
3 years ago Hello Lubomir,
There is an issue in G3 (hdgeant) where the same track number can be assigned to multiple tracks in a given shower if they happen one after another from the same particle. For example, if an electron radiates a photon and stops in the same step, then the photon can carry on with the same track number as the parent particle. Then that photon can undergo the photoelectric effect and stop, leaving an excited electron that then carries on with the same track id. This is an artifact of the way G3 keeps track of secondaries, and is not present in G4. Might that explain what you are seeing, or are you not using the track number recorded in the simulation output?
-Richard Jones
On Wed, Mar 3, 2021 at 4:40 PM pentchev notifications@github.com wrote:
I'm doing MC with both g3 and g4, of the BH reaction with e+e-p in the final state and look at the trees out of the Reaction Filter. To make things easier to explain, http://www.jlab.org/Hall-D/detector/fdc/Mar21_analysis_g34comp.pdf this plot http://url was made by such commands:
epemB3_Tree->Draw("Positron__P4_KinFit.Theta()*57.3","ChargedHypoEnergy_BCAL[PositronChargedIndex]>0&&ChargedHypoEnergy_FCAL[Positron__ChargedIndex]>0&&abs(RFTime_Measured-ThrownBeam__X4.T())<2.")
I don't know what is the criteria to assign hits in the calorimeter(s) to a certain track, but if I look at the other two tracks with the same cuts, their azimuthal angles are very different, so the hits in the two calorimeters are coming from the same track. Also these are not randoms, as there are no such events out of the prompt peak, so the timing selection is not needed.
I see two issues here. There is a difference between the two geants when propagating e.m. showers through the calorimeters. When the electron/positron hits the edge of BCAL (at ~10deg) certainly some photons can escape and hit FCAL, which I see in g3 but not in g4.
As for the two camel humps at theta>10 deg, the problem is mots likely somewhere in the tracking/analysis as it is present in both geants and the energy deposited in the calorimeters doesn't make sense.
Note that in my case, these events represent ~0.1% of all the simulated events.
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pentchev
zihlmann
sdobbs
markito3
I'm doing MC with both g3 and g4, of the BH reaction with e+e-p in the final state and look at the trees out of the Reaction Filter. To make things easier to explain, this plot was made by such commands:
epemB3_Tree->Draw("Positron__P4_KinFit.Theta()*57.3","ChargedHypoEnergy_BCAL[PositronChargedIndex]>0&&ChargedHypoEnergy_FCAL[Positron__ChargedIndex]>0&&abs(RFTime_Measured-ThrownBeam__X4.T())<2.")
I don't know what is the criteria to assign hits in the calorimeter(s) to a certain track, but if I look at the other two tracks with the same cuts, their azimuthal angles are very different, so the hits in the two calorimeters are coming from the same track. Also these are not randoms, as there are no such events out of the prompt peak, so the timing selection is not needed.
I see two issues here. There is a difference between the two geants when propagating e.m. showers through the calorimeters. When the electron/positron hits the edge of BCAL (at ~10deg) certainly some photons can escape and hit FCAL, which I see in g3 but not in g4.
As for the two camel humps at theta>10 deg, the problem is mots likely somewhere in the tracking/analysis as it is present in both geants and the energy deposited in the calorimeters doesn't make sense.
Note that in my case, these events represent ~0.1% of all the simulated events.