[d2n-analysis-talk] LHRS H2 elastic theta structure

[Brad Sawatzky]

Yikes.  Big difference.

Now I really wish we had some elastic data after we fixed the problem
that caused that hole...  Oh well, we'll make do.  Glad we understand
the structure in theta now anyway.

-- Brad

On Thu, 29 Apr 2010, posik at jlab.org wrote:

> Hi all,
> 
> So after today's meeting it was suggested that the dip in the theta
> distribution of the LHRS of the H2 runs could be due to the whole in the
> BB shower calorimeter Since the T5 is a coin trigger and the BB shower I
> believe forms the BB trigger, if the BB has a trigger hole, then the T5
> should inherit this hole.
> 
>  So to see if this is the case I plotted the LHRS "L.tr.tg_th" (th.png)
> and the LHRS theta vs phi (th_ph_mod.png) (see plots below). You will
> notice in the T5 trigger cuts (left plots) there is a dip in the theta
> variable and in the theta vs. phi 2D plot there is a clear hole in the
> acceptance. I also plotted the same variables with the T3 trigger (LHRS
> trigger) the right plots. The dip in theta now goes away and in the 2D
> theta vs phi the acceptance no longer has a hole.
> 
> So it seems as though this theta dip is due to the hole in the BB trigger
> from the shower calorimeter.
> 
> Matt



-- 
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