[Moller_simulation] Fwd: momenta in the simulation/root tree cleanup

[Juliette Mammei]

-------- Original Message --------
Subject: 	momenta in the simulation/root tree cleanup
Date: 	Thu, 18 Oct 2012 14:01:40 -0500
From: 	Juliette Mammei <jmammei at physics.umanitoba.ca>
To: 	wdeconinck at wm.edu, Dustin McNulty <mcnulty at jlab.org>, Seamus 
Riordan <riordan at jlab.org>



Hey guys,

I have a bit of a breather from grant writing, so I popped my head above
water to check out the momenta in the simulation, and discovered a bunch
of issues with the tree in general and the momentum definitions in
particular.

1) For example, "p0" is initiated as a double in the
MollerPrimaryGenAction_elasticep.cc, but is a G4ThreeVector in
MollerSteppingVerbose.cc.
2) px0, 1, 2, py0, 1, 2 and pz0, 1, 2, kineE0, 1, 2, theta0, 1, 2  -
what are they supposed to mean!?!  The 0 and 1 versions are always
exactly 0 in the root tree.  What are kineE_org, theta_org (always 0)!?!
3) The momenta are actually defined as directions with unit length, as
far as I can tell, but the values are not going into the tree.
4) There are other root variables that are always some constant value
process, totXS, diffXS, rate (process is -1, others all zero)

I know that x, y, z are the positions at the detector and x0, y0, z0 are
the vertex positions:

src/MollerAnalysis.cc:      x0 = fTrack->GetVertexPosition().x();

I always assumed that the 1, 2 were for the two moller electrons. We
need to decide on a convention and clean this up a bit.  Dave Armstrong,
Konrad and Julie all requested root files for various uses.  We need the
momenta in there.

Thoughts?  Suggestions? Volunteers?

I want to also add a messenger for the tracking of secondaries.  It is
somewhat related to this.  But my grants don't go in until Oct. 25th and
Nov. 1st, so I suspect I won't be able to spend serious time on this
until then.

Talk to you later,

Juliette

-- 
Dr. Juliette Mammei

Assistant Professor
Department of Physics and Astronomy
University of Manitoba
Winnipeg, Manitoba
R3T 2N2 Canada

Office: 1-204-474-6195




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