12.2. Modules in the Generators Package

Apart from the default settings given in the Generators python modules the generators can also be setup directly and there are special generators not covered in Section 12.1.

Warning

Please use the functions from the Generators python modules to setup event generation if possible.

AafhInput

AAFH Generator to generate non-radiative two-photon events like e+e- -> e+e-e+e-

Package

generators

Library

libaafhinput.so

Parameters

• eventType (str, default=’’)

  Event type

• maxFinalWeight (float, default=1.0)

  maximum expected final weight for rejection scheme (ESFT)

• maxSubgeneratorWeight (float, default=1.0)

  maximum expected subgenerator weight for rejection scheme (ESWE)

• maxTries (int, default=1000000)

  Maximum tries for event generation (ITOT)

• minMass (float, default=0.0)

  minimum invariant mass of generated fermion pair. Will automatically be set to at least 2 times the generated particle mass

• mode (int, default=5)

  decay mode to generate. 1: e+e- -> mu+mu-L+L-, 2: e+e- -> mu+mu-mu+mu-, 3: e+e- -> e+e-mu+mu-, 4: e+e- -> e+e-L+L-, 5: e+e- -> e+e-e+e-. L is a user defined particle (default: tau)

• particle (str, default=’tau-‘)

  name of the generated particle for mode 1 and 4

• rejection (int, default=2)

  Rejection method. 1: apply once for the final event weight, 2: apply for the subgenerator weight and for the final weight

• subgeneratorWeights (list(float), default=[1.0, 1.0, 1.0, 1.0, 1.0, 10.0, 10000.0, 10000.0])

  relative weights of the subgenerators: this must be a list of four or eight values (first four are interpreted as WAP, rest as WBP) which specify the relativ weights for each of the four sub generators. The orginial code states that it the program run most efficient when the maximum weight is equal in all sub generators and that if one wants to be sure that all peaks in the differential cross section are accounted the chance to enter each sub generator should be equal. Values which try to fullfill both conditions are printed at after generation when the output level is set to INFO

• suppressionLimits (list(float), default=[1000.0, 1000.0, 1000.0, 1000000000.0])

  suppression limits for the matrix element calculations. This must be a list of four values, [FACE, FACM, FACL, PROC]. For FACE, FACM and FACL these specify the size of the propagator for which the corresponding spin configurations will be omitted. A value of 1e3 will calculate the dominat part correctly and a very large value compared to the mass (i.e. 1e50) will calculate it exactly. PROC specifies that feynman diagrams which contribute less than 1/PROC of the biggest contribution are omitted. For exact calculation it should be very big but 1e9 should be considerably faster without affecting the result very much

BBBremInput

Generates low scattering angle radiative Bhabha events (Beam-Beam Bremsstrahlung).

Package

generators

Library

libbbbreminput.so

Parameters

• DensityCorrectionMode (int, default=1)

  Mode for bunch density correction (none=0, hard=1 (default), soft=2)

• DensityCorrectionParameter (float, default=1.68e-17)

  Density correction parameter tc (=(hbarc/sigma_y)^2)

• MaxWeight (float, default=2000.0)

  The max weight (only for Unweighted=True).

• MinPhotonEnergyFraction (float, default=1e-06)

  Fraction of the minimum photon energy.

• Unweighted (bool, default=True)

  Produce unweighted or weighted events.

BHWideInput

Generates radiative BhaBha scattering events with BHWide.

Package

generators

Library

libbhwideinput.so

Parameters

• MaxAcollinearity (float, default=180.0)

  Maximum acollinearity angle between finale state leptons/photons [degree]

• MinEnergy (float, default=0.2)

  Minimum energy for electrons in the final state [GeV] (default: 0.2 GeV)

• ScatteringAngleRangeElectron (list(float), default=[15.0, 165.0])

  Min [0] and Max [1] value for the scattering angle [deg] of the electron.

• ScatteringAngleRangePositron (list(float), default=[15.0, 165.0])

  Min [0] and Max [1] value for the scattering angle [deg] of the positron.

• VacuumPolarization (str, default=’burkhardt’)

  Vacuum polarization: off (off - EW off, too), Burkhardt89 (bhlumi), Eidelman/Jegerlehner95 (eidelman) or Burkhardt/Pietrzyk95 (burkhardt)

• WeakCorrections (bool, default=True)

  EW correction ON/OFF

• WtMax (float, default=3.0)

  Maximum of weight (wtmax, default: 3.0), if <0: internal maximum search

BabayagaNLOInput

Generates radiative Bhabha scattering and exclusive two-photon events with the high precision QED generator called BabaYaga@NLO.

Package

generators

Library

libbabayaganloinput.so

Parameters

• DebugEnergySpread (float, default=0.005)

  TEMPORARY SOLUTION! Approximate energy spread per beam (CMS)

• EEMIN (float, default=-1.0)

  Minimum CMS energy of the tagged e-/e+ (GeV)

• EEVETO (float, default=-1.0)

  Minimum CMS energy to veto e-/e+ (GeV)

• EGMIN (float, default=-1.0)

  Minimum CMS energy of the gamma (GeV)

• EGVETO (float, default=-1.0)

  Minimum CMS energy to veto gamma (GeV)

• Epsilon (float, default=1e-07)

  Soft/hard photon separator [fraction of ECMS/2], must be <=1e-7 for ee and mumu, <=1e-5 for gg

• ExtraFile (str, default=’’)

  ROOT file that contains additional information.

• FMax (float, default=-1.0)

  Maximum of differential cross section weight (fmax)

• FinalState (str, default=’ee’)

  Final state: ee (default), mm or gg

• MaxAcollinearity (float, default=180.0)

  Maximum acollinearity angle between finale state leptons/photons [degree]

• MaxPrescale (float, default=1.0)

  Maximum prescale factor (used for maximum differential cross section)

• MinEnergy (float, default=0.1)

  Minimum energy for leptons (ee or mm mode) or photons (gg mode) in the final state [GeV]

• MinEnergyFrac (float, default=-1.0)

  Fractional minimum energy for leptons (ee or mm mode) or photons (gg mode) in the final state [fraction of ECMS]

• Mode (str, default=’unweighted’)

  Mode: weighted or unweighted (default)

• Model (str, default=’matched’)

  Model: ps or matched (default)

• NPhotons (int, default=-1)

  Fixed number of (hard) photons are generated, -1 for any number

• NSKDataFile (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/data/generators/babayaganlo/vpol_novosibirsk.dat’)

  File that contain VP data from Novosibirsk (nsk)

• Order (str, default=’exp’)

  Order: born, alpha, exp (default)

• ScatteringAngleRange (list(float), default=[15.0, 165.0])

  Min [0] and Max [1] value for the scattering angle [deg].

• SearchMax (int, default=500000)

  Number of events used to search for maximum of differential cross section

• TEMIN (float, default=-1.0)

  Minimum CMS angle between the tagged e-/e+ and -z axis (deg)

• TEVETO (float, default=-1.0)

  Maximum CMS theta of e-/e+ in final state (deg)

• TGMIN (float, default=-1.0)

  Minimum CMS angle between the gamma and -z axis (deg)

• TGVETO (float, default=-1.0)

  Maximum CMS angle between the gamma and -z axis (deg)

• UserMode (str, default=’NONE’)

  User mode similar to TEEGG: ETRON, EGAMMA, GAMMA or PRESCALE or NONE (default)

• VPUncertainty (bool, default=False)

  Calculate VP uncertainty by internal reweighting

• VacuumPolarization (str, default=’hlmnt’)

  Vacuum polarization: off, hadr5 (Jegerlehner) or hlmnt (Teubner, default)

• eventType (str, default=’’)

  Event type

BeamParameters

Setting of beam parameters. This module allows to set the beamparameters to be used by generators and analyis. One can either select from a list of predefined parameter sets or manually set the parameters to use.

Package

generators

Library

libgenerators_modules.so

Parameters

• angleXHER (float, default=0.0415)

  angle of the High Energy Ring in the x-z plane. Negative values are interpreted as pi - value

• angleXLER (float, default=-0.0415)

  angle of the Low Energy Ring in the x-z plane. Negative values are interpreted as pi - value

• angleYHER (float, default=0.0)

  angle of the High Energy Ring in the y-z plane. Negative values are interpreted as pi - value

• angleYLER (float, default=0.0)

  angle of the Low Energy Ring in the y-z plane. Negative values are interpreted as pi - value

• covHER (list(float), default=[0.0])

  covariance matrix of the High Energy Ring. This can either be one value which is the squared energy spread, three values corresponding to the variances of energy and the horizontal and vertial spread (E, theta_x, theta_y) or a full covariance matrix with 9 elements

• covLER (list(float), default=[0.0])

  covariance matrix of the Low Energy Ring. This can either be one value which is the squared energy spread, three values corresponding to the variances of energy and the horizontal and vertial spread (E, theta_x, theta_y) or a full covariance matrix with 9 elements

• covVertex (list(float), default=[0.0])

  covariance matrix of the nominal vertex position. Can be either one value which is the common variance for all directions, three values for the variance of x, y and z or a full covariance matrix

• createPayload (bool, default=False)

  if true create a database payload with the iov given with the payloadIov parameter

• energyHER (float, default=7.0)

  Energy of the High Energy Ring

• energyLER (float, default=4.0)

  Energy of the Low Energy Ring

• generateCMS (bool, default=False)

  if true, generate events in CMS, not lab system

• payloadIov (list(int), default=[0, 0, -1, -1])

  iov of the payload to be created. List of four numbers: first experiment, first run, last experiment, last run

• smearDirection (bool, default=True)

  if true, smear beam direction when generating initial events

• smearEnergy (bool, default=True)

  if true, smear energy when generating initial events

• smearVertex (bool, default=True)

  if true, smear vertex position when generating initial events

• vertex (list(float), default=[0.0, 0.0, 0.0])

  nominal vertex position

BoostMCParticles

Module for boosting the MCParticles from CM to LAB frame. The module must be appended to the path only when HepMC, Hepevt or LHE input files are used.

Package

generators

Library

libgenerators_modules.so

Parameters

• MCParticlesStoreArrayName (str, default=’’)

  Name of the MC particles StoreArray.

CRYInput

Generates cosmic showers with CRY.

The showers will be generated in the xz plane in a square plane of n bt n meters centered at the IP (n can be choosen with the boxLength parameter). Then the cosmics will be propagated from there to the boundary of the detector world volume.

Finally, if the track would intersect with the acceptance volume the track is kept. The acceptance volume can be either a sphere, a cylinder or a box centered at the IP. This depends on how many values are given to the acceptance parameter.

Package

generators

Library

libcryinput.so

Parameters

• CosmicDataDir (str, default=’’)

  Directory that holds the cosmic data for CRY. Empty string will look in the default location

• acceptance (list(float), default=[])

  Size of the acceptance volume. This can be either be:

  1. one value being the radius of a sphere

  2. two values for the radius (in xy) and the half-length (in z) of a cylinder

  3. three values for x,y,z half-length of a box

  All volumes are centered around the IP. All values are in cm

• boxLength (float, default=10000.0)

  Length of the side of the square in the xz plane in which CRY will generate cosmics in cm. Will be rounded down to meters. According to the CRY documentation good values are 1, 3, 10, 30, 100 and 300m but anything in between should work as well. The default is 100m and should be fine for almost all use cases.

• date (str, default=’1-1-2019’)

  Date used for the generation: a string in the form of ‘month-date-year’. The cosmic-ray distribution is adjusted to account for the eleven year, sunspot cycle (the default solar minimum date is January 1, 2008).

• kineticEnergyThreshold (float, default=0.01)

  Energy threshold [GeV]

• maxTrials (int, default=10000)

  Maximum number of trials per event

• returnElectrons (bool, default=True)

  Whether or not CRY should return electrons

• returnGammas (bool, default=True)

  Whether or not CRY should return gammas

• returnKaons (bool, default=True)

  Whether or not CRY should return kaons

• returnMuons (bool, default=True)

  Whether or not CRY should return muons

• returnNeutrons (bool, default=True)

  Whether or not CRY should return neutrons

• returnPions (bool, default=True)

  Whether or not CRY should return pions

• returnProtons (bool, default=True)

  Whether or not CRY should return protons

• timeOffset (float, default=0.0)

  Time offset [s]

Cosmics

cosmics generator to generate cosmic ray tracks

Package

generators

Library

libgenerators_modules.so

Parameters

• cylindricalR (float, default=125.0)

  Radius of tube around detector at whose surface particles are generated (in cm), default is 125, but this does not include whole Belle 2 detector!

• ipRequirement (int, default=0)

  Radial and longitudinal constraints near the Interaction Point can be required (ipRequirement == 1), default is 0 (no additional IP requirements)

• ipdr (float, default=3.0)

  Constraint on the radial distance from the IP in cm, default is 3.

• ipdz (float, default=3.0)

  Constraint on the longitudinal distance from the IP in cm, default is 3, default is 3.

• level (int, default=1)

  level of the generator (1 or 2 with slightly different kinematic distributions and mu+/mu- ratio), default is 1

• ptmin (float, default=0.7)

  Minimal value of the transverse momentum in GeV, default is 0.7

EventT0Generator

Module generates discrete event t0 in ~4ns steps (bunch spacing) according to double gaussian distribution and adds it to the production and decay times of MCParticles. This means that after this module the time origin (t = 0) is set to what L1 trigger would give as the collision time. In case of cosmics, the L1 triggerjitter is generated according to a continuos double gaussian distribution

Package

generators

Library

libgenerators_modules.so

Parameters

• coreGaussWidth (float, default=5.6)

  sigma of core gaussian [ns]

• coreGaussWidthCosmics (float, default=13.0)

  sigma of core gaussian for cosmics [ns]

• fixedT0 (float, default=nan)

  If set, a fixed event t0 is used instead of simulating the bunch timing.

• isCosmics (bool, default=False)

  if True simulate L1 jitter for cosmics

• maximumT0 (float, default=nan)

  If set, randomize between -maximum and maximum.

• tailGaussFraction (float, default=0.08)

  fraction (by area) of tail gaussian

• tailGaussFractionCosmics (float, default=0.09)

  fraction (by area) of tail gaussian for cosmics

• tailGaussMeanCosmics (float, default=28.0)

  mean of tail gaussian for cosmics [ns]

• tailGaussWidth (float, default=14.5)

  sigma of tail gaussian [ns]

• tailGaussWidthCosmics (float, default=15.0)

  sigma of tail gaussian for cosmics [ns]

EventT0Shifter

Shift the time of all MCParticles so that the collision time is t=0.It reverts the shift done by the EventT0Generator module and should be used after the simulation.Note that the collisionTime in the MCInitialParticles is not changed.

Package

generators

Library

libgenerators_modules.so

EvtGenDecay

This module decays unstable particles using EvtGen. The event should be already generated by another generator. If you need to generate full event with EvtGen, then use the module ‘EvtGenInput’.

Package

generators

Library

libevtgendecay.so

Parameters

• DecFile (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/decfiles/dec/DECAY_BELLE2.DEC’)

  EvtGen decay file (DECAY.DEC).

• MCParticleColName (str, default=’’)

  MCParticle collection name.

• UserDecFile (str, default=’’)

  User EvtGen decay file.

EvtGenInput

EvtGenInput module. The module is served as an interface for EvtGen Event Generator so that the EvtGen generator can store the generated particles into MCParticles. The users need to provide their own decay mode based on the standard DECAY.DEC.

Package

generators

Library

libevtgeninput.so

Parameters

• CoherentMixing (bool, default=True)

  decay the neutral B meson pairs coherently or non-coherently

• DECFile (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/decfiles/dec/DECAY_BELLE2.DEC’)

  global DECfile to be used

• InclusiveParticle (str, default=’’)

  Inclusive Particle Name

• InclusiveType (int, default=0)

  inclusive decay type (0: generic, 1: inclusive, 2: inclusive (charge conjugate)

• ParentParticle (str, default=’Upsilon(4S)’)

  Parent Particle Name

• eventType (str, default=’’)

  Event type

• maxTries (int, default=100000)

  Number of tries to generate a parent particle from the beam energies which fits inside the mass window before giving up

• userDECFile (str, default=’’)

  user DECfile name

Fragmentation

Fragmention of (u/d/s/c) quarks using PYTHIA8

Package

generators

Library

libfragmentation.so

Parameters

• CoherentMixing (bool, default=True)

  Decay the B0-B0bar coherently (should always be true)

• DecFile (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/decfiles/dec/DECAY_BELLE2.DEC’)

  EvtGen decay file (DECAY.DEC)

• ListPYTHIAEvent (int, default=0)

  List event record of PYTHIA after hadronization

• ParameterFile (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/generators/modules/fragmentation/data/pythia_belle2.dat’)

  Input parameter file for PYTHIA

• UseEvtGen (int, default=1)

  Use EvtGen for specific decays

• UserDecFile (str, default=’’)

  User EvtGen decay file

GeneratedVertexDisplacer

Takes a list of PDG values and lifetime paramters to displaces the vertex of MCParticles with matching PDG value corresponding to the given lifetime parameter. Can be used betwenerator and the detector simulation.

Package

generators

Library

libgenerators_modules.so

Parameters

• ctau (bool, default=True)

  Input unit option. True (default): module expects lifetime as ctau [cm]. False: lifetime as tau [ns].

• lifetime (list(float), default=[0.0])

  Set the numerical value of the lifetime c*tau in units of [cm]. Example: (lifetime_1, lifetime_2, … ,lifetime_N). Lifetime_X is set for PDG_X.

• lifetimeOption (str, default=’fixed’)

  Set the lifetime option, either ‘fixed’, ‘flat’ or ‘exponential’. Option is set globally.

• maxDecayTime (float, default=300.0)

  Set the maximal allowed decay time in c*tau [cm] for the option ‘flat’. The ‘exponential’ option is not bound. Default 300cm.

• pdgVal (list(int), default=[-999])

  PDG values of MCParticles that should be displaced. Subsequent daughters of these will be displaced accordingly. Example: (PDG_1, PDG_2, … , PDG_N). PDG_X corresponds to lifetime_X.

GeneratorPreselection

Preselection based on generator truth information. Returns 0 if no cut have been passed, 1 if only the charged cut has been passed, 10 if only the photon cut has been passed, and 11 if both charged and photon cuts have been passed.

Package

generators

Library

libgenerators_modules.so

Parameters

• MaxChargedTheta (float, default=150.0)

  maximum polar angle of charged particle [deg]

• MaxPhotonTheta (float, default=165.0)

  maximum polar angle of photon [deg]

• MinChargedP (float, default=0.25)

  minimum charged momentum [GeV]

• MinChargedPt (float, default=0.1)

  minimum charged transverse momentum (pt) [GeV]

• MinChargedTheta (float, default=17.0)

  minimum polar angle of charged particle [deg]

• MinPhotonEnergy (float, default=-1.0)

  minimum photon energy [GeV]

• MinPhotonTheta (float, default=15.0)

  minimum polar angle of photon [deg]

• applyInCMS (bool, default=False)

  if true apply the P,Pt,theta, and energy cuts in the center of mass frame

• nChargedMax (int, default=999)

  maximum number of charged particles

• nChargedMin (int, default=0)

  minimum number of charged particles

• nPhotonMax (int, default=999)

  maximum number of photons

• nPhotonMin (int, default=0)

  minimum number of photons

• stableParticles (bool, default=False)

  if true apply the selection criteria for stable particles in the generator

GeneratorPreselectionLeptonic

Filtering based on generator truth information. Returns 0 if cuts have not been passed, 1 only if all cuts are passed.

Package

generators

Library

libgenerators_modules.so

Parameters

• UMax (float, default=10.0)

  maximum value of U = E - p (calculated using vector sum of momenta and energy for neutrinos in CMS)

• UMin (float, default=-10.0)

  minimum value of U = E - p (calculated using vector sum of momenta and energy for neutrinos in CMS)

• angleMax (float, default=1.0)

  maximum value for the cosine of the angle between the tau and signal lepton momentum vectors (in CMS)

• angleMin (float, default=-1.0)

  minimum value for the cosine of the angle between the tau and signal lepton momentum vectors (in CMS)

• projectionMax (float, default=10.0)

  maximum value for projection of tau lepton onto signal lepton momentum (in CMS)

• projectionMin (float, default=-10.0)

  minimum value for projection of tau lepton onto signal lepton momentum (in CMS)

• signalLeptonPDG (float, default=11.0)

  PDG code for the signal lepton

• signalLeptonPMax (float, default=5.0)

  maximum momentum (CMS) for signal lepton

• signalLeptonPMin (float, default=0.0)

  minimum momentum (CMS) for signal lepton

• tauLeptonPMax (float, default=5.0)

  maximum momentum (CMS) for tau daughter lepton

• tauLeptonPMin (float, default=0.0)

  minimum momentum (CMS) for tau daughter lepton

• zDiffMax (float, default=5.0)

  maximum value for difference between production vertex z-component for signal and tau leptons

• zDiffMin (float, default=-5.0)

  minimum value for difference between production vertex z-component for signal and tau leptons

HepMCInput

HepMC file input. This module loads an event record from HEPMC2 format and store the content into the MCParticle collection. HEPMC format is used by for example pythia8.

Package

generators

Library

libhepmcreader.so

Required Parameters

• inputFileList (list(str))

  List of names of HepMC2 files

Parameters

• expNum (int, default=-1)

  Experiment number

• ignoreReadEventNr (bool, default=False)

  Parallel pythia can have dublicate event nrs.

• makeMaster (bool, default=True)

  Boolean to indicate whether the event numbers from input file should be used.

• maxEvt (int, default=2147483647)

  Stop converting at event number.

• minEvt (int, default=-1)

  Start converting at event number.

• nVirtualParticles (int, default=0)

  Number of particles at the beginning of the events that should be made virtual.

• runNum (int, default=-1)

  Run number

• useWeights (bool, default=False)

  Set to ‘true’ to if generator weights should be propagated.

• wrongSignPz (bool, default=False)

  Boolean to signal that directions of HER and LER were switched

HepMCOutput

HepMC file output. This module loads an event record from the MCParticle collection and store the content back into the HepMC (2) format. HepMC format is a standard event record format to contain an event record in a Monte Carlo-independent format.

Package

generators

Library

libhepmcwriter.so

Required Parameters

• OutputFilename (str)

  The filename of the output file

Parameters

• StoreVirtualParticles (bool, default=False)

  Store also virtual particles in the HepMC file.

HepevtInput

HepEvt file input. This module loads an event record from HEPEVT format and store the content into the MCParticle collection. HEPEVT format is a standard event record format to contain an event record in a Monte Carlo-independent format.

Package

generators

Library

libgenerators_modules.so

Required Parameters

• inputFileList (list(str))

  List of names of Hepevt files

Parameters

• expNum (int, default=-1)

  Experiment number

• makeMaster (bool, default=False)

  Boolean to indicate whether the event numbers from input file should be used.

• nVirtualParticles (int, default=0)

  Number of particles at the beginning of the events that should be made virtual.

• runNum (int, default=-1)

  Run number

• skipEvents (int, default=0)

  Skip this number of events before starting.

• useWeights (bool, default=False)

  Set to ‘true’ to if generator weights should be propagated.

• wrongSignPz (bool, default=False)

  Boolean to signal that directions of HER and LER were switched

HepevtOutput

HepEvt file output. This module loads an event record from the MCParticle collection and store the content back into the HEPEVT format. HEPEVT format is a standard event record format to contain an event record in a Monte Carlo-independent format.

Package

generators

Library

libgenerators_modules.so

Required Parameters

• OutputFilename (str)

  The filename of the output file

Parameters

• FullFormat (bool, default=True)

  Write the full HepEvt format to file. Set it to false for a compact format.

• MirrorPz (bool, default=False)

  If the directions of HER and LER are switched, mirror Pz.

• StoreVirtualParticles (bool, default=False)

  Store also virtual particles in the HePEvt file.

InclusiveParticleChecker

Check for the existence of one or more inclusive particles in the list of generated particles. If any of the particles is found the event is accepted and the return value is set to True. Otherwise the return value is set to false.

The particles to look for can either be given as numerical pdg codes or as particle names or even as a mix of both:

>>> checker = path.add_module("InclusiveParticleChecker", particles = [11, "pi+"])

Valid names are defined in the evt.pdl of evtgen and can be inspected using either the pdg module or b2help-particles.

This module is intended for inclusive signal generation where we run a generator which produces generic events and we require a certain particle to be present in the resulting list of particles.

Package

generators

Library

libgenerators_modules.so

Required Parameters

• particles (list(variant(str, int)))

  Name or PDG code of the particles to look for. If any of those is found in the event the event is accepted

Parameters

• includeConjugates (bool, default=True)

  If true look for either the particles or their charge conjugates

KKGenInput

KKGenInput module. This an interface for KK2f Event Generator for basf2. The generated events are stored into MCParticles. You can find an expample of its decay file (tau_decaytable.dat) for tau-pair events at ${BELLE2_RELEASE_DIR}/data/generators/kkmc. On the other hand, when you like to generate mu-pair events, ${BELLE2_RELEASE_DIR}/data/generators/kkmc/mu.input.dat should be set to tauinputFile in your steering file.

Package

generators

Library

libkkgeninput.so

Parameters

• KKdefaultFile (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/data/generators/kkmc/KK2f_defaults.dat’)

  default KKMC setting filename

• eventType (str, default=’’)

  Event type

• kkmcoutputfilename (str, default=’’)

  KKMC output filename

• taudecaytableFile (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/data/generators/kkmc/tau.input.dat’)

  tau-decay-table file name

• tauinputFile (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/data/generators/kkmc/KK2f_defaults.dat’)

  user-defined tau/mu/q-pairs generation setting

KoralWInput

Generates four fermion final state events with KoralW.

Package

generators

Library

libkoralwinput.so

Parameters

• DataPath (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/data/generators/koralw’)

  The path to the KoralW input data files.

• UserDataFile (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/data/generators/koralw/KoralW_eeee.data’)

  The filename of the user KoralW input data file.

• eventType (str, default=’’)

  Event type

LHEInput

LHE file input. This module loads an event record from LHE format and store the content into the MCParticle collection. LHE format is a standard event record format to contain an event record in a Monte Carlo-independent format.

Package

generators

Library

libgenerators_modules.so

Required Parameters

• inputFileList (list(str))

  List of names of LHE files

Parameters

• Rmax (float, default=1000000.0)

  Maximum of distance between displaced vertex to IP in CM frame

• Rmin (float, default=0.0)

  Minimum of distance between displaced vertex to IP in CM frame

• expNum (int, default=-1)

  Experiment number

• makeMaster (bool, default=False)

  Boolean to indicate whether the event numbers from input file should be used.

• meanDecayLength (float, default=0.0)

  Mean decay length(mean lifetime * c) between displaced vertex to IP in the CM frame, default to be zero, unit in cm

• nInitialParticles (int, default=0)

  Number of MCParticles at the beginning of the events that should be flagged c_Initial.

• nVirtualParticles (int, default=0)

  Number of MCParticles at the beginning of the events that should be flagged c_IsVirtual.

• pdg_displaced (int, default=9000008)

  PDG code of the displaced particle being studied

• runNum (int, default=-1)

  Run number

• skipEvents (int, default=0)

  Skip this number of events before starting.

• useWeights (bool, default=False)

  Set to ‘true’ to if generator weights should be propagated (not implemented yet).

• wrongSignPz (bool, default=True)

  Boolean to signal that directions of HER and LER were switched

OverrideGenerationFlags

Ovverride generation flags for BeamParameters from database.

Package

generators

Library

libgenerators_modules.so

Parameters

• generateCMS (bool, default=False)

  Generate events in CMS, not lab system.

• smearDirection (bool, default=True)

  Smear beam direction when generating initial events.

• smearEnergy (bool, default=True)

  Smear energy when generating initial events.

• smearVertex (bool, default=True)

  Smear vertex position when generating initial events.

PairGen

Simple module to generate tracks of given PDG back to back in CMS.

Package

generators

Library

libpairgen.so

Parameters

• pdgCode (int, default=11)

  PDG code for generated particles

• saveBoth (bool, default=True)

  Store both particles if true, one if false

ParticleGun

Particle gun to generate simple tracks. This module allows to generate simple events where all tracks have the same momentum, angular and vertex distributions. Several distributions are available for momentum, phi, theta and vertex position generation:

fixed:

Fixed value, only one parameter has to be specified [value]

uniform:

Uniform between two given values [min, max]

uniformPt:

Generate flat transverse momentum pt [min_pt, max_pt]

uniformCos:

Generate uniformly in the cosine, e.g. flat in cos(theta). Parameters are still the minimum and maximum angle (not the cosine of the angle) [min_theta, max_theta]

uniformLog:

Generate uniformly in the logarithm. Parameters are still the normal values [min, max]

uniformLogPt:

Like uniformLog but for the transverse momentum.

normal:

Normal (Gaussian) distributed [mean, width]

normalPt:

Generate normal distributed transverse momentum pt [mean_pt, width_pt]

normalCos:

Generate normal distributed cosine of the angle [mean, width]

polyline:

Generate according to a pdf given as polyline, first the sorted x coordinates and then the non-negative y coordinates [x1, x2, x3, ... xn, y1, y2, y3, ..., yn]

polylinePt:

Like polyline but for pt, not p

polylineCos:

Like polyline, but for the cos(), not the absolute value

inversePt:

Generate uniformly in the inverse of pt, that is uniform in track curvature [min_pt, max_pt]

discrete:

Discrete Spectrum given as a list of weights and values (useful for radioactive sources) [weight1, value1, weight2, value2, ...]

discretePt:

same as above but for transverse momentum

Package

generators

Library

libgenerators_modules.so

Parameters

• fixedMomentumPerEvent (bool, default=False)

  generates particle momentum according to the specified distribution and assigns this momentum to all particles generated for one event

• independentVertices (bool, default=False)

  If false, all tracks of one event will start from the same vertex, otherwise a new vertex is generated for every particle

• momentumGeneration (str, default=’uniform’)

  Momentum distribution: one of fixed, uniform, normal, polyline, uniformLog, uniformPt, normalPt, inversePt, polylinePt, uniformLogPt or discrete

• momentumParams (list(float), default=[0.05, 3.0])

  Parameters for the momentum generation. Meaning of the parameters depends on the chosen distribution

• nTracks (float, default=1.0)

  The number of tracks to be generated per event. If <=0, one particle will be created for each entry in ‘pdgCodes’. Otherwise N particles will be created and the Particle ID for each particle will be picked randomly from ‘pdgCodes’

• pdgCodes (list(int), default=[-11, 11])

  PDG codes for generated particles

• phiGeneration (str, default=’uniform’)

  Phi distribution: one of fixed, uniform, normal, normalCos, polyline, uniformCos, polylineCos or discrete

• phiParams (list(float), default=[0.0, 360.0])

  Parameters for the phi generation in degrees. Meaning of the parameters depends on the chosen distribution

• thetaGeneration (str, default=’uniform’)

  Theta distribution: one of fixed, uniform, normal, normalCos, polyline, uniformCos, polylineCos or discrete

• thetaParams (list(float), default=[17.0, 150.0])

  Parameters for the theta generation in degrees. Meaning of the parameters depends on the chosen distribution

• timeGeneration (str, default=’fixed’)

  Time distribution: one of fixed, uniform, normal, normalCos, polyline, uniformCos, polylineCos or discrete

• timeParams (list(float), default=[0.0])

  Time offset

• varyNTracks (bool, default=False)

  If true, the number of tracks per event is varied using a Poisson distribution. Only used if ‘nTracks’>0

• vertexGeneration (str, default=’fixed’)

  Vertex (x,y,z) distribution: one of fixed, uniform, normal, polyline or discrete

• xVertexGeneration (str, default=’’)

  X vertex distribution: same options as ‘vertexGeneration’. If this parameter is not specified the value from ‘vertexGeneration’ is used

• xVertexParams (list(float), default=[0.0, 0.001])

  Parameters for the x vertex generation. Meaning of the parameters depends on the chosen distribution

• yVertexGeneration (str, default=’’)

  Y vertex distribution: same options as ‘vertexGeneration’. If this parameter is not specified the value from ‘vertexGeneration’ is used

• yVertexParams (list(float), default=[0.0, 5.9e-06])

  Parameters for the y vertex generation. Meaning of the parameters depends on the chosen distribution

• zVertexGeneration (str, default=’’)

  Z vertex distribution: same options as ‘vertexGeneration’. If this parameter is not specified the value from ‘vertexGeneration’ is used

• zVertexParams (list(float), default=[0.0, 0.019])

  Parameters for the z vertex generation. Meaning of the parameters depends on the chosen distribution

PhokharaInput

Generates radiative return events with PHOKHARA 10.

Package

generators

Library

libphokharainput.so

Parameters

• Alpha (int, default=1)

  Vacuum polarization switch: off (0), on (1, [by Fred Jegerlehner], default), on (2, [by Thomas Teubner])

• BeamEnergySpread (bool, default=False)

  Simulate beam-energy spread (initializes PHOKHARA for every event - very slow).

• BeamResolution (float, default=0.0)

  beamres - beam resolution for pion==11 and pion==12 only

• ChiSW (int, default=0)

  chi_sw: Radiative return(0), Chi production(1), Radiative return + Chi production (2). Works only for pion=11 and pion=12.

• Epsilon (float, default=0.0001)

  Soft/hard photon separator

• FinalState (int, default=1)

  Final state: mu+mu-(0), pi+pi-(1), 2pi0pi+pi-(2), 2pi+2pi-(3), ppbar(4), nnbar(5), K+K-(6), K0K0bar(7), pi+pi-pi0(8), lamb(->pi-p)lambbar(->pi+pbar)(9), eta pi+ pi- (10), chi_c1 production (11), chi_c2 production (12), pi0 g (13), eta g (14), etaP g (15)

• ForceMinInvMassHadronsCut (bool, default=False)

  Force application of the MinInvMassHadrons cut. It is ignored by PHOKHARA with LO = 1, NLO = 1.

• FullNLO (int, default=0)

  full NLO : No(0), Yes(1). Allowed only for ph0=1, nlo=1, fsr=2, fsrnlo=1

• IFSNLO (int, default=0)

  IFSNLO: no(0), yes(1)

• KaonFF (int, default=0)

  Kaon FF: KaonFormFactor constrained(0, default), KaonFormFactor unconstrained(1) KaonFormFactor old(2)

• LO (int, default=0)

  ph0 Born: 1ph(0), Born: 0ph(1), only Born: 0ph(-1)

• MaxInvMassHadrons (float, default=112.0)

  Maximal hadrons/muons invariant mass squared [GeV^2]

• MinEnergyGamma (float, default=0.15)

  Minimal photon energy/missing energy, must be greater than 0.0098 * CMS energy [GeV]

• MinInvMassHadrons (float, default=0.01)

  Minimal hadrons/muons invariant mass squared [GeV^2]

• MinInvMassHadronsGamma (float, default=0.0)

  Minimal hadrons/muons-gamma invariant mass squared [GeV^2]

• NLO (int, default=0)

  1 photon : Born(0), NLO(1)

• NarrowRes (int, default=0)

  Only for m_finalState = 0,1,6,7: No narrow resonances (0, default), J/Psi (1) and Psi(2S) (2)

• ParameterFile (str, default=’/gpfs/group/belle2/group/software/buildbot/release_doc/build/data/generators/phokhara/const_and_model_paramall10.0.dat’)

  File that contains particle properties.

• PionFF (int, default=0)

  Pion FF: KS PionFormFactor(0, default), GS old 1), GS new(2)

• PionStructure (int, default=0)

  For pi+pi- only: f0+f0(600): K+K- model(0, default), no structure model(1), no f0+f0(600)(2), f0 KLOE(3)

• ProtonFF (int, default=1)

  ProtonFormFactor old(0), ProtonFormFactor new(1)

• QED (int, default=0)

  ISR only(0, default), ISR+FSR(1), ISR+INT+FSR(2)

• ReplaceMuonsByVirtualPhoton (bool, default=False)

  Replace muons by a virtual photon (for FinalState == 0 only).

• ScatteringAngleRangeFinalStates (list(float), default=[0.0, 180.0])

  Min [0] and Max [1] value for the scattering angle of pions(muons,nucleons,kaons) [deg], default (0, 180)

• ScatteringAngleRangePhoton (list(float), default=[0.0, 180.0])

  Min [0] and Max [1] value for the scattering angle of photons [deg], default (0, 180)

• SearchMax (int, default=100000)

  Number of events used to search for maximum of differential cross section

• SwitchBeamResolution (int, default=0)

  be_r: without beam resolution(0), with beam resolution(1). Works only for pion=11 and pion=12; (0) assumes exact CMS-Energy, (1) each beam ennergy (=CMS-Energy/2) is smeared with Gaussian distribution of the given variance=BeamResolution**2.

• Weighted (int, default=0)

  generate weighted events

• eventType (str, default=’’)

  Event type

• nMaxTrials (int, default=10000)

  Maximum trials per event

PrintTauTauMCParticles

Print an MCParticle Collection

Package

generators

Library

libgenerators_modules.so

Parameters

• collectionName (str, default=’’)

  Collection to print

• maxLevel (int, default=-1)

  Show only up to specified depth level, -1 means no limit

• onlyPrimaries (bool, default=True)

  Show only primary particles

RemoveMCParticles

Remove particles from the MCParticle Collection.

Warning

At the moment, Relations to that MCParticle collection will become invalid and are not fixed automatically

Package

generators

Library

libgenerators_modules.so

Parameters

• alsoChildren (bool, default=True)

  If true, all children of a particle are removed together with the particle, otherwise children are kept

• collectionName (str, default=’’)

  Collection to perform the cuts on

• maxPt (float, default=0.0)

  Maximum Pt value of Particles to be kept. If smaller or equal to minPt, no cut on Pt is performed

• maxR (float, default=0.0)

  Maximum Rphi value of Particles to be kept. If smaller or equal to minR, no cut on Rphi is performed

• maxTheta (float, default=180.0)

  Maximum theta value of Particles to be kept

• maxZ (float, default=0.0)

  Maximum Z value of Particles to be kept. If smaller or equal to minZ, no cut on z is performed

• minPt (float, default=0.0)

  Minimum Pt value of Particles to be kept. If bigger or equal to maxPt, no cut on Pt is performed

• minR (float, default=0.0)

  Minimum Rphi value of Particles to be kept. If bigger or equal to maxR, no cut on Rphi is performed

• minTheta (float, default=0.0)

  Minimum theta value of Particles to be kept

• minZ (float, default=0.0)

  Minimum Z value of Particles to be kept. If bigger or equal to maxZ, no cut on z is performed

• pdgCodes (list(int), default=[])

  If not empty, cuts will only be performed on particles matching the given PDG codes. To remove all particles with a given code just set maxTheta to 0 and fill this list with all codes to be removed

SADInput

Reads the SAD data from a root file and stores it into the MCParticle collection.

Package

generators

Library

libgenerators_modules.so

Required Parameters

• AccRing (int)

  The accelerator ring: 0 = LER, 1 = HER

• Filename (str)

  The filename of the SAD input file.

Parameters

• PxResolution (float, default=0.01)

  The resolution for the x momentum component of the SAD real particle.

• PyResolution (float, default=0.01)

  The resolution for the y momentum component of the SAD real particle.

• Range (float, default=300.0)

  All particles within the range around the IP are loaded [cm].

• ReadMode (int, default=0)

  The read mode: 0 = one SAD particle per event, 1 = one real particle per event, 2 = all SAD particles per event

• ReadoutTime (float, default=20000.0)

  The readout time of the detector [ns]

• RotateParticles (float, default=0.0)

  Rotate the SAD particles around the nominal beam axis [deg] (just for unphysical tests !!!).

SmearPrimaryVertex

Smears primary vertex and all subsequent vertices of all the MCParticles using the informations stored in BeamParameters.

Package

generators

Library

libgenerators_modules.so

Parameters

• MCParticlesStoreArrayName (str, default=’’)

  Name of the MCParticles StoreArray.

TeeggInput

Generates events with TEEGG.

Package

generators

Library

libteegginput.so

Parameters

• CMSEnergy (float, default=0.0)

  CMS energy [GeV] (default: take from xml)

• CONFIG (str, default=’EGAMMA’)

  Specifies the event configuration (EGAMMA, GAMMA, GAMMAE or ETRON)

• CUTOFF (float, default=0.25)

  Cutoff energy for radiative corrections (in CM frame) (in GeV)

• EEMIN (float, default=2.0)

  Minimum energy of the e- (EGAMMA and ETRON conf.) (in GeV)

• EEVETO (float, default=0.0)

  Minimum energy to veto (GAMMA config with hard rad. corr.) (in GeV)

• EGMIN (float, default=2.0)

  Minimum energy of the gamma (EGAMMA and GAMMA conf.) (in GeV)

• EGVETO (float, default=0.0)

  Minimum energy to veto (ETRON/GAMMA config with hard rad. corr.) (in GeV)

• EPS (float, default=0.01)

  Param. epsilon_s (smaller val. increases sampling of k_s^pbc)

• EPSPHI (float, default=0.0001)

  Param. epsilon_phi (‘cutoff’ of the phi_ks peak)

• FRAPHI (float, default=0.0)

  Fraction of time phi_ks is generated with peak(hard rad corr)

• MATRIX (str, default=’BKM2’)

  Specifies which eeg matrix element (BK, BKM2, TCHAN or EPA)

• MTRXGG (str, default=’EPADC’)

  Specifies which eegg matrix element (EPADC, BEEGG or MEEGG)

• PEGMIN (float, default=0.0)

  Minimum phi sep of e-gamma (EGAMMA config with hard rad. corr.) (in deg)

• PHVETO (float, default=0.0)

  Minimum phi sep to veto (ETRON/GAMMA config with hard rad. corr. (in deg)

• RADCOR (str, default=’NONE’)

  Specifies radiative correction (NONE, SOFT or HARD)

• TEMIN (float, default=20.0)

  Minimum angle between the e- and -z axis (EGAMMA conf. only) (in deg)

• TEVETO (float, default=0.1)

  Maximum theta of e+ in final state (in deg)

• TGMIN (float, default=20.0)

  Minimum angle between the gamma and -z axis (in deg)

• TGVETO (float, default=0.05)

  Maximum angle between the gamma and -z axis(ETRON conf. only) (in deg)

• UNWEIGHTED (int, default=1)

  If true then generate unweighted events

• VACPOL (str, default=’hlmnt’)

  Vacuum polarization: off, nsk (Novosibirsk) or hlmnt (Teubner et al., default)

• WGHT1M (float, default=1.001)

  Maximum weight for generation of QP0, cos(theta QP)

• WGHTMX (float, default=1.0)

  Maximum weight for the trial events

TouschekTURTLEInput

Reads the Touschek data from a TURTLE file and stores it into the MCParticle collection.

Package

generators

Library

libgenerators_modules.so

Required Parameters

• FilenameHER (str)

  The filename of the HER TURTLE input file.

• FilenameLER (str)

  The filename of the LER TURTLE input file.

Parameters

• MaxParticles (int, default=-1)

  The maximum number of particles per event that should be read. -1 means all of the particles are read.

• ReadHER (bool, default=True)

  Set to false to skip reading the HER data.

• ReadLER (bool, default=True)

  Set to false to skip reading the LER data.

• zCoordinate (float, default=50.0)

  Indicates the z-coordinate of the TURTLE particles in the file. (default is 50cm, 400cm is also implemented.)

TrepsInput

Input from TREPS generator (No-tag), Input from TREPS generator for ee->ee hadrons

Package

generators

Library

libtrepsinput.so

Parameters

• ApplyCosThetaCutCharged (bool, default=True)

  Whether to apply cut on \(|cos(theta)|\) for charged particles only.

• ApplyTransverseMomentumCutCharged (bool, default=True)

  Whether to apply cut on the minimal transverse momentum for charged particles only.

• DifferentialCrossSectionFile (str, default=’pipidcs.dat’)

  file name for differential cross section table input. If UseDiscreteAndSortedW is true, the file is used

• MaximalAbsCosTheta (float, default=1.01)

  Maximal \(|\cos(\theta)|\), where \(\theta\) is the final-state particle polar angle.

• MaximalQ2 (float, default=-1.0)

  Maximal \(Q^2 = -q^2\), where q is the difference between the initial and final electron or positron momenta. Negative means no cut.

• MinimalTransverseMomentum (float, default=0.0)

  Minimal transverse momentum of the final-state particles.

• ParameterFile (str, default=’treps_par.dat’)

  parameter file for TREPS input

• UseDiscreteAndSortedW (bool, default=False)

  if true, use WListTable for discrete and sorted W. if false (default), use DifferentialCrossSection

• WListTableFile (str, default=’wlist_table.dat’)

  file name for W-List table input. If UseDiscreteAndSortedW is false (default), the file is used

• eventType (str, default=’’)

  Event type