Useful Reference for Using Pythia in CMSSW

Random Information

Symbol Indication
( ) allowed to fragment
KF flavor code
KS status code, 1-10 remain; >10 allowed to frag/decay
A Beginning of String
I Continuation of String
V End of String

Status Codes

  • Access in CMSSW: GenParticle::status()
  • Access in Pythia: K(I,1)

Status Code Definition
0 empty line
1 undecayed particle OR unfragmented single parton or last unfragmented parton in parton system
2 an unfragmented parton, which is followed by more partons in the same colour-singlet parton system
3 an unfragmented parton with special colour flow information stored in K(I,4) and K(I,5), such that adjacent partons along the string need not follow each other in the event record
4 a particle which could have decayed, but did not within the allowed volume around the original vertex
5 a particle which is to be forced to decay in the next PYEXEC call, in the vertex position given (this code is only set by user intervention)
11 a decayed particle or a fragmented parton, the latter being either a single parton or the last one of a parton system, cf. = 1
12 a fragmented parton, which is followed by more partons in the same coloursinglet parton system, cf. = 2. Further, a B meson which decayed as a B one, or vice versa, because of B–B mixing, is marked with this code rather than = 11
13 a parton which has been removed when special colour flow information has been used to rearrange a parton system, cf. = 3
14 a parton which has branched into further partons, with special colour-flow information provided, cf. = 3
15 a particle which has been forced to decay (by user intervention), cf. = 5.
21 documentation lines used to give a compressed story of the event at the beginning of the event record
31 - 52 miscellaneous

Particle ID's

  • Table of Particle ID's:
    • Access in CMSSW: GenParticle::pdf_id()
    • Access in Pythia: K(I,2)

part_ids.jpg part_ids2.jpg

-- MatthewLeBourgeois - 13 Apr 2007

Topic attachments
I Attachment Action Size Date Who Comment
jpgjpg part_ids.jpg manage 23.2 K 2007/04/13 - 01:39 MatthewLeBourgeois  
jpgjpg part_ids2.jpg manage 23.5 K 2007/04/13 - 03:29 MatthewLeBourgeois  
Topic revision: r3 - 2007/05/09 - 17:49:41 - MatthewLeBourgeois
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