1. Simulation Project Structure and tasks
Simulation Project (G.Cosmo)
Coordination
Geant4
collaboration
Geant4 (J.Apostolakis)
LHC-oriented development and support of Geant4 toolkit
Fluka (A.Ferrari)
LHC-oriented development and support of Fluka
FLUKA
collaboration
Garfield (R.Veenhof)
Development, support and interfaces
Experiments
Validation
Physics Validation & Simulation Framework (A.Ribon)
Validation of the detector simulation MC engines
Generator Services (A.Ribon)
Event generators repository, generator validation, HepMC
MC4LHC
LCG Simulation Project

2. Geant4: Releases, Highlights (1/2)
SFT members contribute in physics (validation and modeling), geometry and integration testing.
Contributed to releases and patches
Releases 9.2 (Dec 2008), 9.2-beta (Jun 08), 9.1 (Dec 07)
Patches (3) were provided to release 9.1 during all of 2008
As agreed with users (incl. LHC experiments)
Exceptional patches to 8.3 and 9.0, back-porting fixes from 9.1 patch 1 (Feb 2008)
Delta Review of Geant4 held 19th-20th Jan CERN
Panel included 3 physicists from LHC experiments
Major changes in integration testing
I. McLaren retired, and G. Folger took over
Undertook move to LCG nightly system for testing
Geometry: new GDML integrated module for reading and writing
EM processes: improved Bremsstrahlung
Relativistic corrections; new process for hadrons
Review panel membership included: Charles Young (ATLAS, SLAC – chair), Fabio Cossuti (CMS, INFN), Andreas Morsch (ALICE, CERN)

3. Geant4: Highlights (2/2) Hadronic Physics Improvements
Hadronic physics is major focus area
Extended validation against further data
For energies around 1 GeV, from 5-15 GeV and at 150 GeV
Improved FTF Fritiof model (re-tuning)
For use in most challenging energy regime: 7-15 GeV
Created new physics lists (FTF_BIC, QGS_BIC)
Improved agreement in rapidity ‘region’ of target
From the re-interaction inside the nucleus of the slow particles created in high-energy part of interaction
Problem in matching of energy response remains
Reported by CMS, ATLAS. Reproduced in simple setups
Ongoing investigation

4. LCG Generator Services
GENSER
Structure stable and used by experiments
24 generators installed (most with different versions)
Available for testing the first version of Pythia built with autotools
First version of a “bootstrap” script to help building GENSER automatically on a laptop
Started migration to SLC5
1 new testing package: MC-Tester
Started evaluation of Rivet and HepMC Analysis Tool for regression testing based on distributions
HepMC
New release in progress, expected in March
MCDB
Under testing in CMS production
LCG Simulation Project

5. LCG Physics Validation
Pion longitudinal shower shapes are ok now; some minor improvements still needed for lateral shapes, and for protons (see LCG note: CERN-LCGAPP )
Main focus now on energy response and resolution
Non-smooth transitions between hadronic models
QGSP_BERT is the default Physics List used in ATLAS and CMS. However, there is a growing interest for FTF_BIC and FTFP_BERT Physics Lists, after recent major improvements in the Fritiof model
smoother energy response than QGSP_BERT
but higher response than QGSP_BERT
LCG Simulation Project

6. LCG Simulation ProjectX,
CMS ECAL+HCAL response:
E_vis / E_beam as a function of the beam energy, for pion and proton beams
S. Banerjee, LCG Physics Validation meeting, 3-Dec-2008
LCG Simulation Project

7. Current LCG Simulation manpower
As of Jan 2009
Geant4
5.10
(6.90)
Infrastructure, performance, management (approx)
2.25
(2.15)
Electromagnetic / Hadronic Physics effort (approx)
2.40
(3.30)
Geometry, tracking, biasing (approx)
0.45
(1.15)
CERN staff (3.00 -> 2.70), CERN fell./assoc./stud. (2.10 -> 3.90)
Physics validation & Framework
0.40
(0.80)
(**)
Validation specific to experiments
0.00
Generator services
2.00
(1.70)
management, documentation/release
0.30
(0.00)
GENSER dev., Validation, MCDB
1.70
Fluka
Garfield (interface library to Geant4)
0.20
Management
0.25
Total
7.95
(9.85)
14.85 in Nov !
(x.xx) Manpower as of July 2009
(**) Missing coordination starting from June 2009 !
LCG Simulation Project