New Generators System (Lina Galtieri 10/89)

A new document is being written. This is a preliminary, incomplete version. To run the latest versions of the High PT physics generators, see the following documents:

ISAJET V6.22

CDF$ROOT:[ISAJET.DEVELOPMENT.DOC]ISAJET_621_EXAMPLE.DOC CDF$ROOT:[ISAJET.DEVELOPMENT.DOC]ISA_BOT_LEP.MEM

PYTHIA V4.9

CDF$ROOT:[PYTHIA.DEVELOPMENT.DOC]PYTHIA_49_EXAMPLE.DOC

HERWIG V2.5

CDF$ROOT:[PYTHIA.DEVELOPMENT.DOC]HERWIG_25_EXAMPLE.DOC
Additional documents can be found in the same areas.

The GENP bank contains all the relevant informations on the event. Its content is explained in Appendix A. Print the following include for details: GENERATOR$LIBRARY:GENP.INC

The particle, generation and Termination codes are given in APPENDIX B.

APPENDIX A : GENP - Generated Particle List Bank

This bank is created as a biproduct of the generation phase of the CDF Monte Carlo package. It provides a list of generated particles and their properties for the current event. The list includes at least all particles which are eventually emitted from the event primary vertex. In general, other non-observable "particles" (e.g. partons) may also be included. The contents of the non-primary vertex particle list is dependent upon which physics event generator is employed.

The GENP bank header values are:

Bank Name GENP
Bank Number 1
Bank Type BNKTMX (Mixed)

where the bank type specification is:

          No. of Datawords/     No. of groups     Bank/Group

                  Entries          per entry         Type Id
           -----------------     -------------     ----------
                 6                   0           Mixed
               ngen                  2           entry count
                 5                   0           Integer*4
                 4                   0           Real*4
               npgen                 0           Integer*4

The GENP bank format is:

Displacement Data

(I*4) Type Description --------- ---- ----------- particle no. 1: 0 I*4 particle type code 1 I*4 parent pointer 2 I*4 daughter pointer 3 I*4 generation code 4 I*4 termination code 5 R*4 x component of particle momentum 6 R*4 y component of particle momentum 7 R*4 z component of particle momentum 8 R*4 mass of particle particle no. 2: . . . . . . 9*ngen R*4 mass of particle number 'ngen' 9*ngen+1 I*4 gen pointer for primary vertex particle 1 9*ngen+2 I*4 gen pointer for primary vertex particle 2 . . . . . . 9*ngen+npgen I*4 gen pointer for primary vertex particle 'npgen'

Notes:

Generated particles are numbered from 1 to ngen. All generated particle properties (except gen pointer) are indexed by the generated particle number.
Particle Type Code. The particle code uniquely identifies the particle type. See the offline document PARTLIST.MEM for a list of particle type codes and associated properties.
Parent Pointer. The parent pointer speficies both the immediate parent of the particle and the initial parton responsible for the eventual production of the indexed particle. Let N1 refer to the generated particle number of the initial parton (the Jet number), and one sets N1 to 0 for for particles which result from beam jets. For HERWIG there is no jet number, but there are normally two parents, so N1 represents the other parent. Let N2 be the particle number of the immediate parent of the particle. Then we define: Parent Pointer = (NKGPAK * N1) + N2 where NKGPAK is a variable of common area /GNPACK/ (C$INC:GNPACK.INC) and it is defined properly in the initialization. Note that its value may depend on the version of CDF package used.
Daughter Pointer. This word specifies the daughter particles associated with the indexed particle. Let Nd be the number of daughters directly resulting from the indexed particle. Let Ni be the generated particle number of the first daughter particle. Since daughters of a common parent are always indexed consecutively, we note that the complete set of generation particle codes for the daughters is then given by the integers Ni through Ni + Nd - 1, inclusive. We then define: Daughter Pointer = (NKGPAK * (Nd - 1)) + Ni where NKGPAK is as described above. Note that Daughter Pointer = 0 for a particle which is emitted from the primary vertex. The specification Daughter Pointer = -1 indicates that the indexed particle has been lost due to some reason of the algorithm (not necessarily the error).
Generation Code. This specifies how/why the indexed particle was created. See Appendix B of this document
Termination Code. This indicates how/why the indexed particle was terminated. See Appendix B of this document.
X,Y,Z Components Of Particle Momentum. Specified in the CDF global coordinate system in units of GeV.
Mass Of Particle. The indexed particle mass as generated is given in units of GeV.
Generation Pointer For Primary Vertex Particle. Those particles which do not decay or terminate (during event generation) are considered the primary vertex products. They are numbered from 1 to npgen, where npgen is always less than or equal to ngen. It is this set of potentially "observable" particles which normally serves as the input particle list to the CDF simulation program. If we let 'i' loop from 1 to npgen, then 'i'th generation pointer gives the generation particle number of the 'i'th primary vertex particle (i.e. a number between 1 and ngen).

APPENDIX B : miscellaneous information

P, G and T codes

For the GENP bank data we use several codes to distinguish various stata of particles besides parent and daughter pointers for them.

P-code: The particle code, including "elementary" particles, as well as physical particles. See OFFLINE documentation PARTICLE, PARTLIST, and INTRO_PART. The complete list of P-codes is presented in PARTLIST which is too long to reproduce here.
G-code: The generation code, to identify the global origins or level in which each particle is generated.
T-code: The termination code, to indicate how the particles end their existence or are transformed to other particles.

In the following, tables of G, and T codes are given. Note that the generation and termination codes used in these tables are different from CDFSIM codes.

                          Table of Generation Code

         (I) Elementary Particles

              1    Beam particle (beam1):  positive z-direction (=proton)
              2    Beam particle (beam2):  negative z-direction (=anti-proton)
              3    Hadronic fire ball to be hadronized M.B.  way (without
                     emitting parton for hard collision)
              4    Hadronic fire ball to be hadronized  M.B.   way  (with
                     emitting of partons)
              5    Leftovers of p after hard scattering
              6    Leftovers of p-bar after hard scattering
              7    Underlying event in PYTHIA
             10    partons  originating  from  initial  state   of   hard
                   collisions
             11    partons from Brems./Splits of final (10,11) partons.
             12    partons from QCD branching (HERWIG)
             13    partons from Cluster splitting
             15    partons    from    Brem/Splits    with     electroweak
                   boson(gamma,W,Z,H)
             20    partons  originating  from  initial  state   of   hard
                   collisions
             21    partons from Brems./Splits of final (20,21) partons.
             23    Partons from cluster splitting (HERWIG)
             25    partons    from    Brem/Splits    with     electroweak
                   boson(gamma,W,Z,H)
             30    partons originating from hard collisions
             31    partons from Brems./Splits of final (30,31) partons.
             32    partons from QCD branching (HERWIG)
             33    partons from cluster splitting (HERWIG)
             34    spectators for heavy quarks (HERWIG)
             35    partons    from    Brem/Splits    with     electroweak
                   boson(gamma,W,Z,H)
             40    partons originating from hard collisions
             41    partons from Brems./Splits of final (40,41) partons.
             42    partons from QCD branching (HERWIG)
             43    partons from cluster splitting (HERWIG)
             44    spectators for heavy quarks (HERWIG)
             45    partons    from    Brem/Splits    with     electroweak
                   boson(gamma,W,Z,H)
             50    partons from Drell-Yan bosons
             51    partons from Brems./Splits of final (50,51) partons.
             55    partons    from    Brem/Splits    with     electroweak
                   boson(gamma,W,Z,H)
             60    partons from Drell-Yan bosons
             61    partons from Brems./Splits of final (60,61) partons.
             65    partons    from    Brem/Splits    with     electroweak
                   boson(gamma,W,Z,H)
             70    partons from physical particles (by weak decays).

        (II) Physical Particles

             90    Hadrons, W, Z, H, resonances,  etc.,  as  intermediate
                   (virtual  or  real)  particles  in  the  s-channel  of
                   hard-collisions.
             95    Hadrons   coming   directly   from   usual    hadronic
                   scatterings of beams.
            100    Hadrons,  gauge  bosons,  H,  leptons  directly   from
                   hard-collisions.
            101    proton   or   its   fragment   from    (quasi-)elastic
                   scattering.
            102    anti-proton  or  its  fragment  from   (quasi-)elastic
                   scattering.
            103    hadrons from fire ball of type 3.
            104    hadrons from fire ball of type 4.
            105    hadrons from p leftovers
            106    hadrons from p-bar leftovers
            107    underlying event in PYTHIA
            1**    electroweak bosons from Brem/Split of 11,21,....parton
            15**    hadronized hadron from **-type "elementary"  particles
                    by phase space distribution.
            16**    hadronized hadron from **-type "elementary"  particles
                    by FF-method.
            17**    hadronized hadron from **-type "elementary"  particles
                    by the other hadronization scheme.
            2***    Physical particles (hadrons,  leptons,  gauge  bosons,
                    etc.)  as  decay  products  of ***-type, 1***-type, or
                    2***-type particles.

                        Table of Termination Codes

        (I) Physical Particles

            0    No decays; observed at primary vertex points.
            1    Decay by weak  interactions  with  T > 10**(-11)  sec,
                 e.g., pi's, K',s and muons (Stable particles).
            2    Decay by weak  interactions  into  physical  particles
                 with  10**(-11) > T > 10**(-13),  e.g.,  tau,  charmed
                 hadrons.
            3    Decay by weak  interactions  into  physical  particles
                 with T < 10**(-13).
            4    Decay by  electro-magnetic  interactions,  e.g.,  pi0,
                 eta.
            5    Decay by strong interactions, e.g., rho's and K*'s.
            6    Conversion to another particle, e.g.,  K0  to  K0S  or
                 K0L.
           30    Decay of a Drell-Yan intermediate boson into a fermion
                 pair.
           31    Decay of Electroweak boson into a  fermion  pair  with
                 radiation
           32    Electroweak Boson involved in hard collision
           99    Lost by some  reason  (e.g.,  FF-jet  cut  procedures,
                 etc.)

         (II) Elementary Particles

          (i) beam particles

          101    Make usual hadronic scatterings of beams.
          102    Form hadronic fire balls without emitting partons.
          103    Emit partons and the  rest  will  form  hadronic  fire
                 balls or leave a color hole in it.

           (ii) Hadronic fire balls

          201    Hadronize as M.B.  way.
          202    Hadronize by longitudinal phase space distributions.
          203    Hadronize by 3-dim.  phase space.
          207    Hadronize by the LUND method.
          208    Hadronize by the Marchesini-Webber method (HERWIG)
          209    Does not hadronize or lost.

           (iii) Partons (quarks and gluons)

          301    Emit Bremsstrahlung or split into other partons.
          302    Make hard collisions.
          305    Hadronize by phase-space distributions.
          306    Hadronize by FF-method.
          307    Hadronize by the LUND method.
          308    Hadronize by the Parton Shower method (HERWIG).
          309    Lost by some reason.
          311    Emit Bream or Split  into  electroweak  bosons  and/or
                 partons

DOCUMENTS FOR FURTHER INFORMATION

CDF OFFLINE NOTES: See, OFFLINE note INDEX, particularly, for a list of documentations.

INTRO_PARTYP.MEM
Introduction to particle type/data system in CDF package.
PARTICLE.MEM
Reference manual of particle data and decay data handling utility in CDF package.
PARTLIST.MEM
Complete list of particle data and decay table of OFFLINE package default.
BNKFORMAT
YBOS bank format for each bank which is included in I/O data of the package.
YBOS USER GUIDE (CDF note 156, by D. Quarrie) must be read in order to understand the data handling of the package.