Multiple track states for TrackClusterMatching

[andresailer]

BEGINRELEASENOTES

• DDTrackCreator: implement passing of multiple track states to Pandora, needs Track states PandoraPFA/LCContent#16

• Implemented DDTrackCreatorBase::GetTrackStatesAtCalo to obtain second trackstate in the endcap

• Added GetTrackStatesAtCalo and related code in DDTrackCreatorCLIC and DDTrackCreatorILD

• DDPandoraPFANewProcessor:

  • added TrackStateTolerance variable to tweak the radius until trackStates in the ECal endcap are accepted, by default only trackStates with a radius larger than EcalBarrel Inner radius are accepted
  • added TrackSystemName parameter to chose trackSystem (DDKalTest) to use for trackState calculation

ENDRELEASENOTES

For my test sample of 2000 10GeV pions in the relevant direction (34 to 36 degrees polar angle) of the CLIC_o3_v13 detector I find the following number of reconstructed particles

Particle	Before	After
Neutron	185	9
Gamma	90	58
Electron	29	35
Muon	20	22
Pi-	1676	1876

A lot less neutrons, so cluster are better matched now. I have only compared the first entries from the ReconstructedParticle collection, so the reconstruction performance is probably even better than what is shown in the table. Sometimes particles shower before reaching the calorimeter, so perfect results cannot be expected.

[gaede]

Should/Could we not have fixed this rather in the MarlinTrk code ?
If I understand your code correctly, it deals with the barrel endcap transition region, where we falsly return the intersection with the barrel rather than with the endcap that is hit a larger radius ?

[andresailer]

We cannot fix this in the MarlinTrk code.
The track intersects both the barrel and the endcap surfaces, it is not clear which one is better because the shower can be more in the barrel or more in the endcap. Thus we need to check both trackstates once we have a cluster.
We tried at the very beginning to reduce the length of the ECal Barrel surface to force having the track state in the endcap surface, but that then caused other problems.

[andresailer]

Necessary changes in PandoraPFA implemented, will merge soon if there are no objections.