[Hps-analysis] FEE Track Matched Clusters

[Holly Vance]

Actually, I remember now that the momentum that is stored is never the GBL
track re-fit momentum.

I am recalculating the momentum using the track fit parameters and B-field
to see if this effect does go away.

On Wed, Oct 7, 2015 at 1:28 PM, Nelson, Timothy Knight <
tknelson at slac.stanford.edu> wrote:

> Sho can comment, but I believe he said the same in his message: that the
> v2 GBL momentum should not have such shifts.
>
> Tim
>
> > On Oct 7, 2015, at 10:25 AM, Holly Vance <hvanc001 at odu.edu> wrote:
> >
> > So I re-ran my code checking that the track type is GBL, and the plots
> look the same. It seems that these effects will be specifically addressed
> in this upcoming pass.
> >
> > On Wed, Oct 7, 2015 at 12:25 PM, Nelson, Timothy Knight <
> tknelson at slac.stanford.edu> wrote:
> > So the GBL track isn’t used for this collection? (I though GBL “healed”
> the v2 momentum scales).
> >
> > T
> >
> > > On Oct 7, 2015, at 9:18 AM, Sho Uemura <meeg at slac.stanford.edu> wrote:
> > >
> > > SeedTracks in v2 geometry have big momentum shifts like what you're
> seeing. GBLTracks have better momentum in v2 than in v1.
> > >
> > > We think this is because v1 has systematic misalignments across the
> detector (e.g. L1-3 vs. L4-6), and v2's misalignments are due to
> measurement error and are less correlated from sensor to sensor. SeedTracks
> are very sensitive to alignment of the first layers of the SVT, so the
> momentum measurement is worse in v2. GBLTrack momentum is in a sense
> "averaged" over the length of the track, so the momentum measurement is
> better in v2.
> > >
> > > SeedTracks are very sensitive to misalignment in
> > >
> > > On Wed, 7 Oct 2015, Nelson, Timothy Knight wrote:
> > >
> > >> Hi Holly,
> > >>
> > >> It turns out the v2 (survey) alignment used in pass 2 is no better
> (and possibly worse) than the v1 (as designed) alignment (the assembly
> error appears to have been as small as or smaller than the survey error,
> where 50 microns is a big effect).  Nonetheless, you shouldn?t be seeing
> those effects with either one, so something is obviously wrong.    I?m not
> sure which track collection is used for the FP Particle collection, but our
> best fits for FEE should have errors at the 1% level, not the 10% level, in
> both top and bottom.
> > >>
> > >> Sho?  Omar? Pelle?
> > >>
> > >> Tim
> > >>
> > >>> On Oct 7, 2015, at 8:20 AM, Graf, Norman A. <ngraf at slac.stanford.edu>
> wrote:
> > >>>
> > >>> Good Morning Holly,
> > >>> I?m sure the experts will also chime in, but I?d like to point you
> to the presentations at
> > >>> yesterday?s SVT meeting where there was quite a bit of discussion of
> alignment.
> > >>> https://confluence.slac.stanford.edu/display/hpsg/10.6.2015+Weekly
> > >>> Omar had also shown some slides (not yet posted) from his analysis
> of the v3
> > >>> detector, which I assume he will be showing either tomorrow or
> Friday.
> > >>> Norman
> > >>>
> > >>> From: Hps-analysis [mailto:hps-analysis-bounces at jlab.org] On Behalf
> Of Holly Vance
> > >>> Sent: Wednesday, October 07, 2015 7:24 AM
> > >>> To: hps-analysis at jlab.org
> > >>> Subject: [Hps-analysis] FEE Track Matched Clusters
> > >>>
> > >>> Hi,
> > >>>
> > >>> I analyzed the skimmed FEE events from pass 2 studying track matched
> clusters at the Ecal. I made a very short summary in the attached pdf, and
> I was wondering if anyone from tracking can comment on why the momentum for
> these tracks is 10% high/low.
> > >>>
> > >>> How well do we know the SVT planes positions? I assume the survey
> cannot tell us this precisely.
> > >>>
> > >>> -Holly
> > >>>
> > >>>
> > >>> _______________________________________________
> > >>> Hps-analysis mailing list
> > >>> Hps-analysis at jlab.org
> > >>> https://mailman.jlab.org/mailman/listinfo/hps-analysis
> > >>
> > >>
> > >> _______________________________________________
> > >> Hps-analysis mailing list
> > >> Hps-analysis at jlab.org
> > >> https://mailman.jlab.org/mailman/listinfo/hps-analysis
> > >>
> >
> >
> >
> > --
> >
> >
>
>
>
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