[d2n-analysis-talk] Transversity BB shower class

[Brad Sawatzky]

On Tue, 13 Jul 2010, posik at jlab.org wrote:

>   I have just finished a replay of run 2060, a 4-pass 3He run, using our
> data base, with transversity's BB total shower class. This class differs
> from our current BB total shower class, because it has more checks of
> the found clusters in the shower/ps with reconstructed tracks and finds
> and saves multiple clusters, where as the d2n BB total shower class only
> finds and saves the largest cluster.

That sounds like a good improvement.  It'll be nice to roll that into
our analyzer.

>   In the plots attached, I compared some variable replayed using the d2n
> lib to the transversity lib. The plots done using the transversity BB
> total shower lib are prefixed with trans_xxx.png and those done using
> the d2n total shower are prefixed d2n_xxx.png.
> 
>   All plots have the following cuts:
> 
>     (DBB.evtypebits&1<<2)==(1<<2) && BB.optics.vzflag==1 &&
> BB.optics.charge==-1 && BB.tr.p>0.2
> 
>   I plotted E/p (Ep0.png), the preshower energy (ps1.png), the preshower
> with no chareg particle cut (ps0.png) the shower energy (sh0.png) the
> momentum (p0.png) and the preshower energy (y-axis) vs  E/p (x-axis)
> (en.png)
> 
> There are more tracks found in the transversity replayed lib and there

I understood that the cluster identification depended on the
reconstructed track.  Are you saying that the track reconstruction
depends on the Shower too?  That is, how does a change to the shower
class change the number of tracks?

I believe we still need the final optics calibration completed for BB.
Is that correct?  Have you and Diana worked out who is in charge of that
part?

> seems to be more events found in the lower preshower range. This is
> evident in the preshower plots and the ps vs E/p plots. By applying a
> negative particle cut, a lot of the lower preshower hits went away,compare
> to trans_ps0.png which shows the preshower with no charged particle cut. I
> think that these lower preshower events are because we are now not saving
> just the largest energy cluster?

The trans_ps1.png plot has more hits below the 200 threshold seen in the
the d2n_ps1.png plot.  Does that make sense?

-- Brad

-- 
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
The most exciting phrase to hear in science, the one that heralds new
  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov