1 / 23

Recent Developments and Validations in Geant4 Hadronic Physics

Dennis Wright (SLAC) CALOR 2006 5-9 June 2006. Recent Developments and Validations in Geant4 Hadronic Physics. Fan Lei (Qinetiq) Nikolai Starkov (CERN) Pete Truscott (Qinetiq) Hans-Peter Wellisch Dennis Wright (SLAC). Geant4 Hadronic Contributors. Gunter Folger (CERN)

jacie
Download Presentation

Recent Developments and Validations in Geant4 Hadronic Physics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dennis Wright (SLAC) CALOR 2006 5-9 June 2006 Recent Developments and Validations in Geant4 Hadronic Physics

  2. Fan Lei (Qinetiq) Nikolai Starkov (CERN) Pete Truscott (Qinetiq) Hans-Peter Wellisch Dennis Wright (SLAC) Geant4 Hadronic Contributors • GunterFolger(CERN) • AatosHeikkinen(Helsinki) • VladimirIvantchenko(CERN/ESA) • TatsumiKoi(SLAC) • MikhailKossov(CERN) 2

  3. Outline • Elastic scattering (improvements) • Parameterized model (improvements) • Cascade models (improvements, validation) • High energy models (cross section comparisons) • Shower shape studies (testing a combination of the above models) 3

  4. ElasticScatteringImprovements • Elastic scattering is important for shower shapes • Existingmodelisjustadequate,needsimprovement • non-relativistickinematics,parameterizedtofitmostlyforwarddata,chargeexchangeincluded,nocoherenceeffects • Newmodelandprocess(G4UHadronElasticProcess, G4HadronElastic)availablewith8.1release • highprecisionneutroncrosssectionsfor E < 20 MeV • relativistically correct • chargeexchangeremoved(willbeincludedasinelastic) • improvedtreatmentofp,nscatteringfromp,d,a • coherence effects included (diffraction minima) above 1 GeV 4

  5. ElasticScattering 5

  6. Parameterized ModelImprovements • Parameterizedmodel(lowenergyandhighenergyparts)isare-engineeredversionofGHEISHA • basedon fits to data with some theoretical guidance • can be used for all long-lived hadrons + light ions • not originally intended to conserve most quantities on an event-by-event basis, but rather on average (does well in showers) • Improvementsfor8.1releaseincludebetterenergyconservation,nucleoncountinginlowenergypart(<25GeV) • Similarimprovementstohighenergypartinrelease9.0 6

  7. ParameterizedModelTestinILCCalorimeter (Ron Cassell - SLAC) 7

  8. Cascade ModelImprovements • TwocascademodelsofferedbyGeant4 • binary:twoparticlecollisionsonly,withresonanceformationanddecay,forp,n,p(<3GeV ) • Bertini:basedonINUCLcode,scatteringbasedonfree-spacecrosssections ( < 10 GeV) • Binarymodelextendedtoheavyions ( Aprojectile < = 12) or (Atarget < = 12), E < 10 GeV/A • Bertinicascadeextendedtokaons,hyperons • plannedextensiontoelasticscatteringandheavyions 8

  9. CascadeValidation 9

  10. High Energy Models • Geant4hasthreemodelsforhighenergies(15GeV<E<~10TeV): • highenergyparameterized (HEP) : derived from GHEISHA, depends mostly on fits to data with some theoretical guidance • quark-gluonstring(QGS):theoreticalmodelwithdiffractivestringexcitationanddecaytohadrons • Fritioffragmentation(FTF):alternatetheoreticalmodelwithdifferentfragmentationfunction • Ofthetwotheoreticalmodels(QGSandFTF)QGSseemstoworkbetterinmostsituations • MostusedandtestedmodelsareHEPandQGS 10

  11. HighEnergy Model Validation:rapidity 11

  12. HighEnergy Model Validation:transverse momentum 12

  13. HighEnergy Model Validation:kinetic energy at 70 degrees 13

  14. HighEnergy Model Validation:kinetic energy at 90 degrees 14

  15. HighEnergy Model Validation:kinetic energy at 118 degrees 15

  16. Shower Shape Studies • TouseGeant4inarealisticsimulationmanymodelsandprocessesmustbecombinedinaphysicslist • two physics lists, LHEP and QGSP, are the most used and most tested Geant4 physics lists in high energy calorimetry • LHEP consists of the low energy parameterized (LEP) and high energy parameterized (HEP) models, plus the Geant4 standard electromagnetic package • QGSP consists of the Quark-gluon string model (QGS), the Precompound model and some of the LHEP models plus the Geant4 standard electromagnetic package • Datafromseveraltestbeamexperimentshavebeencomparedtothepredictionsofthesephysicslists • Showershapesprovideespeciallygoodtests 16

  17. Shower Shape Studies • ThefollowingcomparisonsarebasedondatafromtheCMStestbeam • CMStestbeamsetup (2004): • ECAL: 7 x 7 array of PbWO4 crystals • HCAL: 2 barrel production wedges of alternating brass absorber and scintillator • pion beams from 2 to 300 GeV • SimulationusedGeant4 6.2 p02 and looked at: • recovered energy • pion energy spectra • longitudinal shower shapes 17

  18. Slide courtesy of J. Damgov, S. Piperov, S. Kunori and the CMS collaboration

  19. Slide courtesy of J. Damgov, S. Piperov, S. Kunori and the CMS collaboration

  20. Slide courtesy of J. Damgov, S. Piperov, S. Kunori and the CMS collaboration

  21. Slide courtesy of J. Damgov, S. Piperov, S. Kunori and the CMS collaboration

  22. Other Developments and Validations • HARPdatatobepublishedsoon • 1–15GeVtestbeamdata (p, n, p) • veryusefulforcascademodelvalidation • Alternatephysicslist:LCPHYS • used in linear collider studies • test beam validation within the year? • Geant4 cross section review • all hadronic cross sections to be checked and updated • internal cross section in QGS model already improved -> possible improvement in shower shapes at high energy 22

  23. Summary • Many improvements to the Geant4 hadronic models are being made in order to improve calorimeter response and shower shape agreement • Elastic scattering was found to be important to shower shape – improvements being made • Cascade models are important for calorimetry – both Geant4 models are being validated – more data needed • Shower shapes measured in CMS test beam show good agreement at low to medium energies – high energy models may need improvement 23

More Related