[ROOT] small requests for TParticle, TParticlePDG and TMCParticle

From: Costas Andreopoulos (C.V.Andreopoulos@rl.ac.uk)
Date: Wed Nov 17 2004 - 19:55:25 MET


Hello,

I am working on a ROOT-based neutrino event generator
http://hepunx.rl.ac.uk/~candreop/generators/GENIE/
for the MINOS experiment.

Some small requests:

<TParticlePDG/>

TParticlePDG's Lifetime() always returns 0.
(I do run TDatabasePDG::ReadPDGTable("...") first).
This leads to some nastiness when I am trying to
figure out which of the particles in the event record
should be passed to a particle decayer. I only need 
to decay the particles with very small lifetimes:
eg a pi^0 but not a pi^+. 
It would be great if TParticlePDG's Lifetime() was
fixed so that I could base my decision on that.


<TParticle/>

The essence of the generated event record is that it is
a TClonesArray of TParticles. However, some of the particles 
involved in the interaction are nuclei that do not fit very 
well in a TParticle.  Internally, I do have some specialized
classes that hold a nuclei and look up nuclear physics tables
for getting the nuclear properties. But, for passing my event
records to the outside world it would be very usefull if TParticle
could hold a nucleus (eg by having a special pdg-code and some
methods for setting/getting Z,A - and possibly a couple of methods
to set/get some very basic additional properties like a 
'bool fIsExcitedState'...


<TLorentzVector/>

Things would be a little bit easier for me if TParticle & TMCParticle
had a consistent interface for getting the 4-momentum and, specifically,
something that involves returning a TLorentzVector rather than
individual components.

cheers,
      Costas

-- 
Dr. Constantinos Andreopoulos, CCLRC - Rutherford Lab.
http://hepunx.rl.ac.uk/~candreop



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