FWD Software

["Ogawa, Akio" <akio AT bnl.gov>]

Hello

Jason and his team has been working on Geant4star. He is now asking for help on its validation using FCS:

Jason wrote:

I think the geant4star validation is at a point where it would be useful to start doing more

rigorous testing of the calorimeters against data and starsim.  For the FCS, I was wondering

if you could (or have) identified anyone who would be interested in working on this.  Ths goal is to

wrap this up by the end of August.

Please see Geant4STAR Task Force meeting (esp Yousif’s):

https://drupal.star.bnl.gov/STAR/meetings/STAR-Collaboration-Meeting-March-2026/Geant4STAR-Task-Force

and his talk at STAR CM:

https://drupal.star.bnl.gov/STAR/meetings/STAR-Collaboration-Meeting-March-2026/Plenary-session-III/GEANT4-task-force-report

As you can see in Yousif’s work, it is already giving sensible results for FCS with muons, EM and hadrons, at least for mean energy loss.

 

I think next step would be comparing G3 vs G4 with clusters using reasonable thresholds (which comes naturally with digitization and clustering with existing code) instead of total sum of dE of all FCS towers without thresholds. Then we should get to the comparisons of energy resolutions, not just mean energy loss (~=sampling fraction). I expect G3 and G4 differences will be most obvious when it comes to hadron analysis, both in how widely spread hadronic showers are (and we may need to adjust cluster finder parameters or even algorithms…remember… current cluster finder for HCal was never really tested nor optimized beyond single hadron MC), and how we add ECal and HCal contributions to get to hadron energy.  And then of course data vs MC comparisons come (but we need to calibrate Hcal first).

Jason, please add if you have more things to look at.

Please let us know if you are interested in working on this project. 

Thans!

Akio