1. Outline: ILC physics focus hadronic showers data and simulation requests from other HEP experiments some considerations G4 for the ILC and other non-LHC HEP experiments Erika Garutti (DESY) Vasily Morgunov (DESY / ITEP) Note: focus of the talk is on medium energy hadronic physics does not cover low energy experiments (< 1 MeV) and electromagnetic processes

2. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 2 ILC: e + e - collider (~ 33 km), √s = 500 GeV – 1 TeV machine for discoveries beyond SM and precision measurements Future of particle physics GEANT4 at the GEANT4 @ ILC is used in: the accelerator design - for example in the BDSIM package for background and collimation studies (high energy muon production and beam gas interactions) - studies of Beam Delivery System and Integrated Luminosity Performance ( EuroTeV ) - beam polarization studies (with additional EM processes) the detector design - all aspects, i.e. particle transport in high magnetic field, tracking, electromagnetic and hadronic shower simulation,… Main linacs Electron source IP Positron source Dumping rings

3. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 3 Future of particle physics Physics at the ILC benchmark reactions proposed by P. Zerwas Hadronic final state  transport in high B

4. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 4 New Physics: - rare processes/limited statistics Many final states involving heavy bosons (Z,W,H): e + e -  WW, e + e -  ZZ Hadronic decay of W and Z - branching ratio ~70% - result in two hadronic jets Requires excellent  E jet =60%/ √E  E jet =30%/ √E Mj 1 j 2 Mj 3 j 4 Mj 1 j 2 Mj 3 j 4 Jet Energy Resolution to resolve  M W-Z = 9.76 GeV ALEPH ILC Future of particle physics Physics at the  New algorithm: Particle Flow

5. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 5 A new detector concept Particle Flow stresses: reconstruction of each particle in an event separation of particles replacement of E with tracking momentum Less important: single particle energy resolution in calo. Detector requirements: good tracking, in particular in dense jets excellent granularity in the ECAL good granularity in the HCAL excellent matching between tracker / ECAL / HCAL 2004200520062007200820092010 R&D Phase / Design Detector concepts engineering design Mean E of interest in ILC hadronic event E  ~5-10GeV (LHC E jet > 20 GeV) ILC detector time scale LHC input

6. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 6 The ILC simulation frameworks Development and comparison of different detector concepts At present different frameworks for simulation, but unique output format (persistency frame LCIO) to allow same reconstruction and analysis 4 th concept not yet integrated in the same framework but also makes use of G4

7. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 7 From Jeremy McCormick (SLAC, LDC simulation group)

8. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 8

9. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 9 CALICE: from MC to reality Intermediate task: Build prototype calorimeters to Establish the technology Collect hadronic showers data with unprecedented granularity to - tune reconstruction algorithms - validate existing MC models Final goal: A high granularity calorimeter optimised for the Particle Flow measurement of multi-jets final state at the International Linear Collider CAlorimeter for the LInear Collider Experiment Si-W ECAL Scint. Tiles-Fe AHCAL Scint. Strips-Fe TCMT Imaging calorimeter

10. 10 The test beam prototypes Si-W Electromagnetic calor. 1x1cm 2 lateral segmentation 1 X 0 longitudinal segment. ~1 total material Scint. Tiles-Fe hadronic calor. 3x3cm 2 lateral segmentation ~4.5  in 38 layers Scint. Strips-Fe Tail Catcher & Muon Tracker 5x100cm 2 strips ~5  in 16 layer 10 GeV pion shower @ CERN test beam

11. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 11 The CERN installation HCAL Tail Catcher ECAL beam One of the 38 HCAL layers with high granular core readout

12. E. Garutti 12 Event display Shower from a 40 GeV  + 20 GeV  + HCAL only REAL DATA! Clear structure visible in hadronic showerBack-scattered particle

13. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 13 HCALTCMT 40GeV/c pion with CALICE online analysis software Late shower in HCAL Clear determination of the first interaction Event display REAL DATA!

14. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 14 Hadron event EM-like hit : E>4 MIP HAD-like hit: E>1.8MIP & E<4MIP Track-like hit: E>0.5MIP & E<1.8MP DATA ECAL HCAL reconstruction algorithm: Deep Analysis (V. Morgunov)

15. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 15 Event with 2 hadrons (distance ~6 cm) DATA ECAL HCAL

16. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 16 Event with 2 hadrons after reconstruction. Two showers separated in depth are visible reconstruction algorithm: Deep Analysis (V. Morgunov) applied to HCAL only clusters grouped according to topology and hit amplitude Separate: EM and HAD shower components + neutrons (= isolated hits) DATA ECAL HCAL

17. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 17 Deep Analysis of hadronic shower New generation of calorimeters offers unprecedented capability to resolve intrinsic structure of hadronic shower used to  discriminate between different hadron models  improve two particle separation in calorimeter  improve energy resolution It provides a NEW type of differential benchmark for MC comparison, intermediate between integrated and double differential cross sections

18. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 18 Getting ready to compare data/MC G3 G4 study performed in 2003 by V. Morgunov on 10 GeV  GHEISHA Neutron transport Bertini MICAP Total energy in GeV

19. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 19 Models comparison Geant3 Geant4 2% 4-5% 60% Bertini Energy correction coefficient = E_generated / E_reconstructed GHEISHA Integrated quantities Materials, geometry, energy cutoff optimized to be as similar as possible (@ 2% level, see muon)

20. E. Garutti 20 Digital HCAL record only the cell which are hit no amplitude information small cells: imagining HCAL Correspondence between energy and number of cells hit Energy (GEV) Number of cells hit Tile (analog) HCAL record the position and amplitude Hadronic CALO: analog or digital? Analog Digital (0.5x0.5) Digital (1.4x1.4) Digital (2.5x2.5) Digital (3.0x3.0) E [GeV]  /E low E  low E  digital better than analog due to suppressed Landau fluctuations high E  high E  analog better than digital  Conclusion dependent on E density from simulation !!!

21. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 21 Models comparison Integrated quantities G3 G4 GHEISHANeutron transportBertini different correlation MICAP !! Important for simulation of digital calorimeter

22. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 22 Models comparison Differential quantities The HCAL high granularity offers the possibility to investigate longitudinal and lateral shower shapes with unprecedented precision: - 38 points for longitudinal profile (if ECAL and TCMT included up to 84) - 9 points for lateral profile Study on hadronic shower profiles, G. Mavromanolakis (2004)

23. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 23 CALICE Pre-PRELIMINARY ECAL ongoing analysis Longitudinal shape Lateral profile beam-line description in MC not completed

24. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 24 A deeper comparison Binding / Lost Energy = E beam – (E EM + E HAD ).vs. # of reconstructed neutrons Shower composition New benchmark for data/MC comparison

25. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 25 The ILC request to G4 The ILC community has to design, optimize and compare concepts of the next generation of HEP detectors The most controversial part for simulations is the hadronic sector The energy of interest for ILC hadronic physics is lower than that of LHC (mean E  ~5-10 GeV, @ 500 GeV  s) In this energy range hadronic models in G4 are sometimes inadequate or outdated CALICE can offer to G4 the possibility of active collaboration in comparing and tuning all models with unique precision and new benchmark parameters For our community it is convenient to work within one framework but it is vital to have available all intra-nuclear cascade models (from FLUKA and MCNP) A clear set of expert-recommended parameters is needed to ease the user task

26. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 26 The rest of the non-LHC community F. Gaede and C. Young collected answers to a poll among HEP experiments: here reported only the comments concerning additional physics request to G4 MINOS / NOVA Try to migrate from G3 to G4, problems with geometry, no phys request yet NUMI (beamline simulation) Default G3+FLUKA, started with G4, request to use FLUKA MiniBooNE G4 only for neutrino flux prediction  p-Be interaction (100MeV – 10 GeV) Request broader range of models, in particular FLUKA BaBar Finished validation of G4.7, improvements compared to G4.6, proceed to G4.8 no additional physics requests Also other experiments have replied which do not use G4: Belle, STAR and PHENIX (RHIC), OPERA, K2K/T2K (because of no FLUKA), KEK/E391, J-PARK/E14 (not yet, planed if FLUKA)

27. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 27 The rest of the non-LHC community FLUKA G3+GHEISHA G4+QGSP G4+QGSP+Bert Preliminary studies for the KOPIO project (from Joseph Comfort) K L and n beam-line under consideration for future experiment (secondary beam production from 30 GeV/c protons on Ni)  Simulate 4 GeV/c K L, K +, p +, n beams on 1cm cube lead, look momentum and  spread “differences such as these (up to 2-4 between FLUKA and GEANT4) can be very disturbing for proposals for experiments, …, in our application the FLUKA results were more favorable.” Large differences between models at medium energies

28. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 28 ITS 3.0 CSDA/decay Models Custom Models Custom Models Decay Models/EEDL, EADL Models Production Decay ITS 3.0 CSDA/decay Production Decay Leptons Electrons Muon Neutrino Other Cont. (ENDF) Models Model list: Bertini JAM>3 GeV Cont. (ENDF) Models Model list: Custom CEM LAQGSM DPMJET Multigroup(72) Models Model list: PEANUT(GINC) +DPM+Glauber Cont. (ENDF) Models Model list: Hadron-nucleous GHEISHA* INUCL(Bertini) BIC CHIPS QGS/FTF>8 GeV Cont. (ENDF) Models Cont. (ENDF) Models Model List: Bertini ISABEL CEM INCL FLUKA89>3 GeV LAQGSM (2.6.C) Baryons Neutron Low High Proton Low High Other CSDA Bethe-Bloch Moliere Vavilov No CSDA Bethe-Bloch Moliere improved Custom No CSDA Bethe-Bloch Moliere improved Custom No/yes CSDA Bethe-Bloch Lewis Urban Yes CSDA Bethe-Bloch Rossi Vavilov No Charged particles Energy loss Scatter Straggling XTR/Cheren. 384168 34Particles PHITSMARSFLUKAGEANT4MCNPXPhysics Gregg McKinney et al. Hadronic shower simulation workshop FNAL, September 2006 The community wishes Include intra-nuclear cascade models from FLUKA and MCNP Maybe integration of nuclear transport has less priority !?

29. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 29 Additional Remarks Comments/suggestions collected: Request of improvement of default parameter sets possibility: multiple recommended sets for different users  not all uses are MC experts, choice from experts is normally the best Request to improve geometry: more flexible definition and debug (GUI), possibility to interface to existing programs (CAD) Both BaBar and Bell are interested to know how good are hadronic interactions in G4 for B and super-B factories Offers of cooperation from the users: Some users have offered to collaborate with GEANT4 on areas where they have particular expertize and interest, e.g. polarized EM processes (DESY Zeuthen), hadronic showers model validation (CALICE) Is GEANT4 interested in such collaboration? How should users proceed?

30. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 30 Final consideration The HEP community is looking forward to a set of models for all energy regions, which does not describe all experiments but does describe NATURE … thank you

31. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 31 Backup

32. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 32

33. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 33

34. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 34

35. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 35

36. E. GaruttiGEANT4 review - CERN, 16-20 April 2007 36 Calorimeter geometry optimization:  Shower separation Generate two 10 GeV showers initiated by  + and K 0 L Use track information for  + Use complete shower reconstruction algorithm (V. Morgunov) Test three options of tile size and readout scheme: - 1 layer of 3x3 cm 2 tiles (best “realistic” case) - 2 layers of 3x3 cm 2 tiles (worse long. segment.) - 1 layer of 5x5 cm 2 tiles (worse lateral segment.) ideal Compare to ideal particle flow algorithm Key issue: High Granularity Key issue: High Granularity  KL0KL0  true E A. Raspereza G3