questions on TClonesArray theory / Event class

From: Jeff Templon (templon@studbolt.physast.uga.edu)
Date: Fri Feb 11 2000 - 22:11:01 MET


Hi Root,

I think I am beginning to understand Rene's comment that it would be
better if I created a simple event class to handle my Tree filling
tasks [see the thread I started about two weeks ago].  All the Event
class examples I have seen so far are filling TClonesArrays of Tracks.

The question: something about the name Clone suggests to me that my
objects will lose their identity if I make them part of a
TClonesArray; that is I would not be able to associate a particular
member name with that object later on.  I want to be able to say
something like T->Draw("ppsi.Mag()") So it would appear that I should
not use a TClonesArray since I want to know easily which particle is
which in later analysis (and since there are not many particles
produced).

Also, suppose I have some TLorentzVector objects which for some events 
are present, but others not.  How do I prevent old values from showing 
up in the tree?  Can I just set the object equal to zero (as some of
the examples seem to do with unitialized objects)?

Thanks for any help.

					Jeff



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