Differences between Sim09 versions

Below is a list of all Sim09 versions, quickly describing new features and known issues. Fixes to problems of previous versions are not explicitly listed

Sim09l

Please see https://gitlab.cern.ch/lhcb/Gauss/-/issues/41

• First Gauss version used: v49r22
• Update of Bc_VHAD model to include new decays
• New signal allowed with EPOS
• Improvement in polarisation exchange between starlight and EvtGen
• Bug fix for a generator level cut. See LHCBGAUSS-2468 and !792

Sim09k

Please see https://gitlab.cern.ch/lhcb/Gauss/-/issues/18

• First Gauss version used: v49r20
• cut for diBoson events !672
• new decay model for hyperons !676
• bug fix in a decay model for Bs -> mu mu K K, triggering the new Sim09 version !693
• new 4-body phase-space decay model in restricted mass window

Sim09j

Please see https://gitlab.cern.ch/lhcb/Gauss/-/issues/11

• First Gauss version used: v49r18
• New decay models in EvtGen, MR !626 (merged) and port of !568 from master/HepForge. Does not effect physics

• Update and new models in AmpGen, MR !640 (merged), triggering letter change
• Allow axions to be generated with StarLight, !643 (merged)
• Fix issues with gluons from Pythia8 without end vertex, !645 (merged), should not effect physics, but triggers letter change

Sim09i

• First Gauss version used: v49r17
• new default PDF for SuperChic2 (https://gitlab.cern.ch/lhcb/Gauss/-/issues/9)

Sim09h

• First Gauss version used: v49r14
• Fixed Sim09g problem in EvtGen itself
• Many updates to AmpGen, see https://gitlab.cern.ch/lhcb/Gauss/merge_requests/438
• New model for Lc2pKpi

Known issues

• Broken signal particle gun

Sim09g

• First Gauss version used: v49r13
• Only bug-fixes
• Change of SIMCOND tags for 2017 and 2018, see details at https://its.cern.ch/jira/browse/LHCBGAUSS-918

Known issues

• Pythia8 can generate a10 that EvtGen cannot decay, resulting in infinite loop (does not affect physics)
• Broken signal particle gun

Sim09f

• First Gauss version used: v49r12
• First release for 2018
• Fix for angular model for $\Lbz \rightarrow \Lz\lepp\lepm$
• Fix for BeautyTomuCharmTo3h to select oscillated particles

Known issues

• Underlying event multiplicity due to handling of wide resonances, see https://indico.cern.ch/event/787606/contributions/3272825/attachments/1830771/2998119/Sim09c_vs_def.pdf
• 2017+2018: Incorrect ECAL threshold used (same as 2016 data)

Sim09e

• First Gauss version used: v49r11
• First release for 2017
• Changes to quarkonia from Pythia8, see https://its.cern.ch/jira/browse/LHCBGAUSS-1167.

Known issues

• Underlying event multiplicity due to handling of wide resonances, see https://indico.cern.ch/event/787606/contributions/3272825/attachments/1830771/2998119/Sim09c_vs_def.pdf
• 2017: Incorrect ECAL threshold used (same as 2016 data)

Sim09d

• First Gauss version used: v49r10
• Updated particle properties (when Pythia called by EvtGen), for decays to partons
• Resonance from Pythia with non-zero width
• Modified model for $B_c^-\rightarrow\Dstz\mum\antinumu$

Known issues

• Underlying event multiplicity due to handling of wide resonances, see https://indico.cern.ch/event/787606/contributions/3272825/attachments/1830771/2998119/Sim09c_vs_def.pdf

Sim09c

• First Gauss version used: v49r8
• Set correctly incorrect ECAL threshold for 2016
• New major DecFiles version and corresponding ParticleTable for light baryons
• Fixes to EvtDDalitz (for \Dp)
• Fixed incorrect handling of $\Bs\rightarrow \bar{K}^{*}\mup\mum$, see https://its.cern.ch/jira/browse/LHCBGAUSS-1097
• Change of DDDB tag for all years and SIMCOND tags for 2015 and 2016, see details at https://its.cern.ch/jira/browse/LHCBGAUSS-918

Known issues

• None

Sim09b

• First Gauss version used: v49r5
• First release for 2016
• Fixed 2nd metal layer handling
• Updated $\tau$ handling with Tauola
• Change in SIMCOND tag for 2016, see https://its.cern.ch/jira/browse/LHCBGAUSS-918

Known issues

• 2016: L0 ECAL calibration correct (but incorrect in data)

Sim09a

• Generators: * 2015: lower tracking $\epsilon$ due to 2nd metal layer problem * EvtGen updated to PDG2014 particle properties
• Geant4 9.6, no significant differences observed
• VELO: error parameterisation and 2nd metal layer parameterisation

Known issues

• 2015: lower tracking efficiency due to 2nd metal layer problem

-- DominikMueller - 2019-06-24