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

Juliette Mammei jmammei at physics.umanitoba.ca
Fri Oct 26 11:08:42 EDT 2012

-------- 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

1) For example, "p0" is initiated as a double in the
MollerPrimaryGenAction_elasticep.cc, but is a G4ThreeVector in
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,


Dr. Juliette Mammei

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

Office: 1-204-474-6195

-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://mailman.jlab.org/pipermail/moller_simulation/attachments/20121026/27017ee8/attachment.html 

More information about the Moller_simulation mailing list