[d2n-analysis-talk] z_react Check Via Focal Plane Cuts

[Brad Sawatzky]

Good plots.  Put these in your next report for sure.

What you've got is really pretty good for our purposes -- I wouldn't
spend too much time trying to make it better.  The worst case is about
a 5mm shift in vertex position.  As long as we keep that in mind when we
apply our cuts and do our systematic studies, we should be fine.

-- Brad

On Tue, 04 May 2010, David Flay wrote:

> Hi all,
> 
> Attached are a few plots to test our optics after implementing
> Transversity's matrix elements and the offset I applied.
> 
> I plot the focal plane (plot 1 -- S1 track x vs. S1 track y) and I divided
> it up into 9 regions (plot 2).  Then, I plotted z_react with basic trigger
> cuts, along with the nominal positions (vertical red lines) and overlayed
> z_react subject to each of the 9 different cut regions (plot 3).
> 
> You will notice that the middle three regions line up very nicely w.r.t.
> the nominal positions.  The edge regions (in particular, the left side)
> have an offset to them, if you look closely (most visible under the
> central peak).  Due to this, I think it's necessary to take a look at
> Transversity sieve data and see how our DB can reconstruct the sieve. I'd
> also like to compare our z_react widths to that of Transversity's.
> 
> The cut regions are not all of equal size, but I think it's still a fair
> test to see how things look -- since an arbitrary cut region should
> ideally reveal a nicely reconstructed vertex.
> 
> Dave


-- 
Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
Ph: 757-269-5947  -<>-  Fax: 757-269-5235  -<>- Pager: brads-page at jlab.org
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