zihlmann
commented
6 years ago At the wirebased fit stage there is a tendency to loose the more downstream hits mostly of package 4.
However at the time based stage some of the hits are recovered in the Geant3 version but not in
the Geant4 version. This indicates that the FDC timing is not the same in geant3 and geant4.
This clearly shows that there is an issue with the wirebased tracking algorithm.
the plot below shows the wirebased fit result and the hits/pseudohits that were used.
Note that all hits in package 4 and most of package 3 are not used anymore. They were at
the candidate stage.
The second issue with the geant4 simulation is that quite frequently the event has no FDC hits at all!!!!
rjones30
T-Britton
jrstevenjlab
This sample included all of Richards flags including: DCAY 0 LOSS 2 MULS 0 DRAY 0
protons at 4 GeV and 15 deg. look equivalent but at 4 degrees:
HDGeant4 missing hits on track
very different wirebased trackingFOM
without multiple scattering we expect the tracking to overestimate the errors, thus causing a pile-up at a CL at 1, as it does with hdgeant. hdgeant4 does not.
You can get access to all of the reconstruction plots via the sept 11 meeting page, many differences to be seen