CERN Accelerating science

Minutes Technical Forum 23-Mar-2020

Minutes of 23 March 2020 Meeting of Geant4 Technical Forum
Editor: A. Morsch, 23 March 2020
- Starting at 16:00

Introduction
============
+ see slides for detail
- Geant4 version 10.6 patch01 released February 14h
- Next release early December 2020
  - Beta release end of June
- Feedback on workplan is welcome !


Patch release 10.6-p01 and 2020 work plan - non-physics part
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+ see slides for details

Patch release 10.6-p01 and 2020 work plan - EM physics part
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+ see slides for details

Patch release 10.6-p01 and 2020 work plan - Hadronic physics part
=================================================================
+ see slides for details
- Clarification S3: G4HadronInelasticDataSet : fixed wrong Gheisha cross section
  - Does not affect the main reference physics lists
  - true for 10.6, but could effect 10.5 and earlier, to be investigated 

Open requirements
=================
+ see slides for details
- Commnent NA62
Geant4 offers a biasing method for forcing collisions (see example
GB02). However, after a discussion with Marc, we found out that this 
only works for neutral particles. Since NA62 uses a K+ beam, a biasing 
with forced collisions for charged particles would allow for generating 
samples of useful statistics within a reasonable time to study the rare
inelastic interactions in  thin material in more detail.



**** New Requirements from Experiments

ATLAS
=====
+ see slides for details
- In 10.6 tests ATLAS spotted an issue with G4MagInt_Driver having a slightly different
implementation than G4IntegrationDriver (already present in 10.4)

CMS
===
+ see slides for details
- Comparisons of predictions from Geant4 versions 10.4.p03 and 10.6.p01
with test-beam and collision data show agreement within statistical
uncertainty

Constraining the anti-deuteron nuclear inelastic cross-section with ALICE
=========================================================================
+ see slides for details
- Constraints on sigma_inel(anti d) point at steeper rise at low momentum than implemented by Geant4
- Request: proper treatment of hypertriton in the propagation
  - Currently treated as a normal nucleus, but from its structure is more like a halo-nucleus
  - If available, similar study as presented today will be possible for hypertriton in the future