From: hagel@comp.tamu.edu
Date: Fri Jun 20 2003 - 22:42:44 EDT
Hello,
I have updated the BrFsGlobalFit module and I used it for the p+p data and on
the surface it appears to at least be "doing no harm". With luck it is even
doing things better. The module now does a real minuit fit to the tracks
(albeit Simplex).
To use it, just put in the script right after the BrFsTrackingModule the statement:
BrFsGlobalTrackFitModule *fit = new BrFsGlobalTrackFitModule("FS","FS");
swModule->AddModule(fit);
The module uses as input the list of FsTracks. It loops over the tracks, does
the fits and modifies the p, theta, phi and vertex of the BrFsTracks it finds
from the list.
I must make several warnings about the module. Indeed, it is being committed at
this "early" time because of the possibility of usefullness in the high pt paper
analysis. The warnings are:
1. I have been doing this in the context of last years p+p. I did not do
anything on purpose to preclude its immediate use for Au+Au or d+Au, but my
experience on the other side of the fence has been that if something is
developed for one system, things for the other system often get overlooked.
2. I fit only the tracks that have a complete FS track. Ie, I use only
BrFsTracks and then only if they have both a FFS and a BFS track. A FFS track
with no BFS track does not benefit from a fit (I guess) and I do not yet know
how to handle a BFS track without a FFS track. Since those exist and appear to
have been purposely built, I hope that soon someone will tell me how to handle
these tracks. For the moment I remove them from the list. (at least I think I do)
I have also committed two changes in bdst. One is in the BdstTrack where I have
added fP and fMethod as data members. The other is in BdstFsTrackModule where
fMethod is set to BdstTrack::kFfsTrack if p, theta, phi and the vertex come from
the BrFfsTrack (when there is no BfsTrack pair in the BrFsTrack list), fMethod
is set to BdstTrack:kFsTrack if p, theta, phi and vertex come from the BrFsTrack
obtained from the FsTrack list. In this case, if the BrFsGlobalTrackFit module
has been called after the FsTracking module, these will be the fit tracks.
I hope this will be useful for the high pt analysis. Let me know if there are
any problems and I will try to solve them as soon as possible (assuming they are
not intractable)
Happy analysis
Kris
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