Annotated Jobcard "jobHarp"

The jobcard explained here in little bit more detail is the file "jobHarp" from Release 1.2. This jobcard may be used in order to calculate particle spectra in pion or proton induced reaction on nuclei. The designated energies are 3 upto 50 GeV, as e.g. possible within the HARP and NA61/Shine experiments.

For more information we refer to our ​online documentation

!************************************************************ -*- fortran -*-
!* A JobCard for BUU:
!* ==================
!*
!* This JobCard tries to be a template for all 
!*       "HiEnergy pion+Nucleus" 
!* collisions.
!* Selected parameters are suitable for HARP and NA61/SHINE
!* calculations
!* 
!************************************************************

!************************************************************
! General Input :
!************************************************************
$input
      eventtype   = 12          ! HiPion

Here we select the initialization routine which is responsible for pion/proton induced reactions. The final state particles are treated perturbatively.

      numEnsembles= 100         ! number of ensembles

The number of ensembles the code treats in the one run. Together with num_runs_SameEnergy (below) responsible for the statistics to collect in the total run. If no potentials are switched on and also the particle density is calculated analytically (as in the given example here), only the total number numEnsembles*num_runs_SameEnergy matters. (Nevertheless, the larger numEnsembles, the more memory the code occupies.)

      numTimeSteps= 100         ! number of time steps
      delta_T     = 0.10        ! time step size

How many time steps the propagation calculates after the first collision before it assumes, that the detector has been reached (and the size in fm). Here we propagate in total 10 fm after the first collision. After this instable particles are forced to decay and the analysis routines are called.

      set_length_perturbative = .TRUE.
!      length_perturbative = 500  ! adjust according target nucleus
      length_perturbative = 2000 ! adjust according target nucleus
!      length_perturbative = 4000 ! adjust according target nucleus

Here we set the size the code should allocate for the perturbative particle vector of the final state particles. The actual array size is numEnsembles*length_perturbative times the number of bytes we need to store all information for one individual particle. For larger target nuclei you need more possible entries. On the other hand you should not choose the vector too large, since you may run into problems with memory. Additionally, although almost empty, a particle vector chosen too large may also slow down the code. Depending on energy, process type and size of target nucleus one should find a compromise. A good hint is the line #### pertParticles is occupied by xxx% with yyy% ensembles over 80% the code prints every timestep.

!      num_runs_SameEnergy=10000  ! number of runs per energy
      num_runs_SameEnergy=2  ! number of runs per energy

(see above)

      localEnsemble = .TRUE.

BUU calculations may be done in parallel ensemble method, full ensemble method and (in our code) in local ensemble method, which is a full ensemble method with local collision criteria (see e.g. ​A.Lang, phd thesis, Gießen, 1991 (in german)).

      freezeRealParticles = .TRUE.

      DoPrLevel(1) = .FALSE.
      DoPrLevel(2) = .FALSE.

      path_To_Input = '~/WC/buuinput'

$end

$LesHouches
!      LesHouchesFinalParticles_Pert=.true. ! if you want that output
$end

$initRandom
      SEED=45678                ! Seed for the random number
$end

$initDensity
      densitySwitch=2           ! 1=dynamic, 2=analytic
$end

$initPauli
      pauliSwitch=2             ! 1=dynamic, 2=analytic
$end

$propagation
      coulomb=.false.           ! Whether to use coulomb in propagation
      predictorCorrector=.false. ! Whether to use a predictor/corrector algorithm
$end

!************************************************************
!	Input for potentials
!************************************************************

$Coulomb
      CoulombFlag=.false.
$end

$mesonPotential
      noPerturbativePotential=.true. ! perturbative mesons feel no potential
$end

$baryonPotential
      noPerturbativePotential=.true. ! perturbative baryons feel no potential
$end

$Yukawa
      yukawaFlag=.false.        ! whether Yukawa is switched on/off
$end

$width_Baryon
      mediumSwitch_coll=.false.
$end


$baryonWidthVacuum
      use_cutoff=.true.
$end


!************************************************************
!	Input specific for the reactions
!************************************************************

$target
!      fermiMotion = .FALSE.
!      target_Z=  1, target_A=  1 ! proton,neutron, deuterium
!      target_Z=  4, target_A=  9, densitySwitch_Static=4 ! Be
!      target_Z=  6, target_A= 12, densitySwitch_Static=4 ! C
      target_Z=  6, target_A= 12 ! C
!      target_Z=  7, target_A= 14 ! N
!      target_Z= 10, target_A= 20 ! Ne
!      target_Z= 16, target_A= 32 ! S
!      target_Z= 26, target_A= 56 ! Fe 
!      target_Z= 29, target_A= 64 ! Cu
!      target_Z= 36, target_A= 84 ! Kr
!      target_Z= 54, target_A=131 ! Xe
!      target_Z= 82, target_A=208 ! Pb
$end

!************************************************************

$HiPionNucleus           ! EVENTTYPE = 12
      distance=10.              ! distance of pions to nucleus
      impact_parameter=-99      ! impact-parameter<0: impact-parameter integration
      DoProton=.TRUE.
      charge=1                  ! charge of pions
      numberPions= 25           ! number of pions per ensemble

!      ekin_lab=515.             ! kinetic energy in system where nucleus rests

!      ekin_lab = 2.205 ! p= 3GeV
!      ekin_lab = 4.149 ! p= 5GeV
!      ekin_lab = 7.117 ! p= 8GeV
!      ekin_lab =11.099 ! p=12GeV
      ekin_lab = 30.000 ! T2K


      doPerturbativeInit=.TRUE. ! Do perturbative init
      DoOnlyOne = .TRUE.
      minimumMomentum=0.1       ! minimum momentum for particles to propagate
$end



!************************************************************
!          The collision term
!************************************************************

$collisionTerm
      energyCheck=0.100         ! accuracy of energy check in GeV
      twoBodyProcessesRealReal = .FALSE.

!      oneBodyProcesses=.false.
!      twoBodyProcesses=.false.
!      threeBodyProcesses=.false.
$end

$insertion
      minimumEnergy=0.100       ! minimal kinetic energy of produced nucleons (GeV)
$end

$master_2Body
      correctEnergy_message=.false.
$end


!************************************************************
! Temperature and thermodynamics
!************************************************************
$initThermoDynamics
      temperatureSwitch=1 ! 1=groundstate calculations (T=0,mu=E_F)
$end


!************************************************************
! Additional Pythia Parameters
!************************************************************
$pythia
      PARP( 91) = 0.44     ! width intrinsic kT
      MSTP( 21) = 21       ! selection of main routine
$end