Track *abandoned* due to excessive number of Zero steps. Event aborted

[vlimant]

This request in production https://cmsweb.cern.ch/reqmgr2/fetch?rid=cmsunified_task_HIN-HINPbPbSpring23GS-00066__v1_T_250129_122614_7425 is failing quasi systematically with

%MSG-w SimG4CoreApplication:  (NoModuleName) 29-Jan-2025 22:20:36 UTC pre-events

-------- EEEE ------- G4Exception-START -------- EEEE -------
*** G4Exception : GeomNav0003
      issued by : G4Navigator::ComputeStep()
Stuck Track: potential geometry or navigation problem.
  Track stuck, not moving for 25 steps.
  Current  phys volume: 'tob:TOBRadServices6_6'
   - at position : (782.8922723338304,845.9646902571437,-1131.000000994178)
     in direction: (0.5216341708152286,0.537228850456787,-0.6627842439850153)
    (local position: (-782.8922723338304,845.9646902571438,-3.499999005822247))
    (local direction: (-0.5216341708152283,0.5372288504567871,0.6627842439850152)).
  Previous phys volume: 'tob:TOBSideDisk_2'

  Likely geometry overlap - else navigation problem !
 Track *abandoned* due to excessive number of Zero steps. Event aborted.


 CMS info: TrackID=3518289 ParentID=3517938  gamma; Ekin(MeV)=480.312; time(ns)=5.25426; status=0
   position(mm): (782.892,845.965,-1131); direction: (0.521634,0.537229,-0.662784)
   PhysicalVolume: tob:TOBRadServices6_6; material: tobmaterial:TOB_rad_services6
   stepNumber=305; stepLength(mm)=1e-07; weight=1; creatorProcess: Decay; modelID=-1

-------- EEEE -------- G4Exception-END --------- EEEE -------

%MSG
----- Begin Fatal Exception 29-Jan-2025 22:20:36 UTC-----------------------
An exception of category 'Geant4 fatal exception' occurred while
   [0] Processing  Event run: 1 lumi: 6017 event: 794203 stream: 0
   [1] Running path 'RAWSIMoutput_step'
   [2] Prefetching for module PoolOutputModule/'RAWSIMoutput'
   [3] Calling method for module OscarMTProducer/'g4SimHits'
----- End Fatal Exception -------------------------------------------------

the log of a failing job can be found here /eos/cms/store/logs/prod/recent/PRODUCTION/cmsunified_task_HIN-HINPbPbSpring23GS-00066__v1_T_250129_122614_7425/HIN-HINPbPbSpring23GS-00066_0/cmsgwms-submit13.fnal.gov-3530277-0-log.tar.gz and /afs/cern.ch/user/v/vlimant/public/ppd/cmsgwms-submit13.fnal.gov-3530277-0-log.tar.gz

[cmsbuild]

cms-bot internal usage

[cmsbuild]

A new Issue was created by @vlimant.

@Dr15Jones, @antoniovilela, @makortel, @mandrenguyen, @rappoccio, @sextonkennedy, @smuzaffar can you please review it and eventually sign/assign? Thanks.

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[makortel]

assign simulation

[cmsbuild]

New categories assigned: simulation

@civanch,@kpedro88,@mdhildreth you have been requested to review this Pull request/Issue and eventually sign? Thanks

[civanch]

This happens for the 1st time. Before we never have problems for gamma - navigation is much more simple than charged particle case.

This case should be studied in details. Without debugging cannot comment.

@bsunanda , have ever seen similar problem?

[bsunanda]

I observed this type of warning in physics lists FTFP_BERT_EMY. I have reported this in many Simulation meetings in the past

…

________________________________ From: Vladimir Ivantchenko ***@***.***> Sent: 02 February 2025 03:41 To: cms-sw/cmssw ***@***.***> Cc: Sunanda Banerjee ***@***.***>; Mention ***@***.***> Subject: Re: [cms-sw/cmssw] Track *abandoned* due to excessive number of Zero steps. Event aborted (Issue #47223) This happens for the 1st time. Before we never have problems for gamma - navigation is much more simple than charged particle case. This case should be studied in details. Without debugging cannot comment. @bsunanda<https://github.com/bsunanda> , have ever seen similar problem? — Reply to this email directly, view it on GitHub<#47223 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ABGMZOQAPONCCB7YK42ZWNT2NVBCZAVCNFSM6AAAAABWHUDDF2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDMMRZGEZTOMBXGE>. You are receiving this because you were mentioned.Message ID: ***@***.***>

[civanch]

@bsunanda , all reported cases were for low-energy e+-, rarely for protons. Here we have gamma of 405 MeV in tracker, which is really new. May it be that there is an overlap, which is not seen on statistics we use for overlap checks ? Here we have HI simulation with huge number of particles.

[civanch]

@vlimant , please consider this fix, which may too early to introduce into master but this definetly will reduce number of exceptions in the HI campaign.

[vlimant]

Thanks @civanch for #47251 .
I think I saw this error in some non-HI simulation, is the fix for all types of simulation ? I am assuming yes, but want to confirm

[civanch]

@vlimant , it is kind of work around for any type of simulation. For the HI case more particles produced before and inside tracker, so this situation is more probable. Is it possible to know in which other campaigns this is observed?

[vlimant]

unfortunately I cannot recall where else I have seen it