[Rivet] finalstate projection with assymetric beam

[Pierog, Tanguy (IKP)]

	Hi,

	In our group we try to develop new analysis for RIVET to test models for 
cosmic ray simulations. For that we use old data with fixed target 
experiments and pion beam for instance. Trying to do some xF (feynman x) 
distributions using pz of course we notice that the pz we get in Rivet are 
all -pz of the hepMC file. We suppose that the "FinalState" projection is the 
only possible reason (or a bug, but this would have been found before I 
guess ...). Is it possible that using "FinaleState" projection the proton 
side (which is the target here) is forced to become the "positive" side 
resulting in a change of the sign of all pz ? If yes, how can it be changed ? 
We tried to find that in the documentation it was not obvious and we didn't 
find any example.

	Just in case, we have an other question: is there an easy way to convert from 
lab frame (hepmc) to center-of-mass (rivet) frame (using this projection may 
be ...) ?

	Thanks for your help and sorry if these are stupid questions ...

	best regards and happy new year

		Tanguy


-- 

_________________________________________________________________________
Dr. Tanguy Pierog, Institut fuer Kernphysik, Campus Nord
Karlsruher Institut fuer Technologie,  Postfach 3640,  D-76021 Karlsruhe,  
Germany
Tel: +49-721-608-2-8134  Fax: +49-721-608-2-4075  e-mail: 
tanguy.pierog at kit.edu
KIT - University of the State of Baden-Wuerttemberg and 
National Laboratory of the Helmholtz Association