Particle Decay Chain Meeting, September 11, 2013

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Present: Matt Shepherd, Kei Moriya, Mark Ito, Beni Zihlmann, Paul Mattione

We met to discuss Kei's recent presentation on problems he is having decoding the decay chain in Monte Carlo events.

He first presented the issues at the September 9th Physics Meeting. Find his slides here. He also prepared some slides incorporating changes made since that meeting and presented them at this meeting. Find those slides here.

Action Items

  1. eta prime will be added to so that it has a chance of being named in the decay chain -> Beni
  2. eta prime and omega0 will be marked with negative type to supress decay in pythia and allow geant to do the decay. That way they can be identified as parent particles in the chain. Note that this is in the default configuration file; it can be changed in the file if an individual wants decay in pythia. -> Beni
    1. We will check with the experts whether the decay model in GEANT is good enough to handle these extra decays. -> Mark
    2. We will review the list to see if there are other particles that should be handed to geant for decay -> Beni
  3. The dimension of map between geant track numbers and myid needs to be lengthened from 100 to 10,000 to allow for large geant track numbers. -> David
  4. We would like to find the document describing the "mechanism" codes used in pythia. -> Mark
  5. genr8_2_hddm should be modified to fill in pdgtype. -> David
  6. We should review the mechanism to suppress the addition of particles in an electromagnetic shower to the list of daughter particles appearing in the output event. -> defer for now
  7. We should write a DMCThrown factory with tag "primary" that returns only the particles input to geant. -> Paul