Re: [Brahms-dev-l] track vertex issue

From: flemming videbaek <videbaek@rcf.rhic.bnl.gov>
Date: Thu Jul 29 2004 - 08:51:41 EDT
Hi Djamel,

we have had some of this discussions before.
There are two issues at hand here
-- with auau we have always DEFINED the trackvertex to be the beam-beam
vertex, and it has worked well, after
    requiring that the diffwerence between (bbVtx and Projected track  is
small  this projection can be either
    on the beamline or bB plane it does not matter apart from a different
sigma.
-- since we also deal with dAu, and pp and possible also with lighter ions
where there may not be a BB vertex, we do need to save the projected VtxZ
also - it should not be replaced by bbVtx - I the later analysis one need to
have access to different vtx's from the global when making decisions.  The
issue is thus one of FS track lengths as you point out neeed for TOF

Since you always have access to the BbVtx in any analysis is it not better
then to let the TrkvtxZ be the proper
projected z (regardless of the witdhs), calculate the lenght as needed. I
think so. Otherwise add one more
variable ..

flemming



----------------------------------------------------------------
Flemming Videbaek
Physics Department
Brookhaven National Laboratory

e-mail: videbaek@bnl.gov
phone: 631-344-4106
----- Original Message ----- 
From: "Djamel Ouerdane" <ouerdane@nbi.dk>
To: "Brahms Devel List" <brahms-dev-l@lists.bnl.gov>
Sent: Thursday, July 29, 2004 6:17 AM
Subject: Re: [Brahms-dev-l] track vertex issue


> Ok, here is my fix :
>
> in the event method, Kris already picked up the BB vertex for some check.
> All I did is the following : if it turns out that the track vertex in Z is
> equal to the bb vertex (as done in BrFfsTrackingModule for AuAu), then
> I don't reevaluate the track vertex. Therefore, the module still works as
> before in case the BB vertex was not used before during the FFS tracking.
>
> I committed the changes and changed the brat version to 2.22.6 and tagged
> it BRAT-2-22-6. But something will follow soon because of the magnet swim
> status and some fiducial cut stuff. Stay tuned. Once all of this is done,
> then I will rerun the condor scripts for gtr and dst (this is kind of fast
> and runs properly). But please, when you want to jump to some physics
> analyses (I know it's more fun), check first the basic stuff (reco level).
>
> Djam
>
>
> -- 
> Djamel Ouerdane ------------------------------------------o
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